Optimization of sol–gel coatings on the surface of aluminum

Optimization of sol–gel coatings on the surface of aluminum
Optimization of sol–gel coatings on the surface of aluminum

Optimization of sol–gel coatings on the surface of aluminum

pigments for corrosion protection

Lijun Li *,Pihui Pi,Xiufang Wen,Jiang Cheng,Zhuoru Yang

School of Chemical and Energy Engineering,South China University of Technology,Guangzhou 510640,China

Received 19June 2007;accepted 2November 2007

Available online 24November 2007

Abstract

Encapsulated aluminum pigments were prepared by sol–gel method using tetraethoxysilane (TEOS)and vinyltriethoxysilane (VTES)as precursors.The reaction conditions were optimized and the aluminum pigments prepared under the optimum conditions were char-acterized by Fourier transformation infrared spectroscopy (FTIR),scanning electron microscopy (SEM)and X-ray photoelectron spec-troscopy (XPS).Subsequently the stability of the aluminum pigments in acid and alkaline aqueous media was examined.It was found that both TEOS and VTES hydrolyze and condense to form a dense netlike layer on the surface of aluminum pigments.XPS analysis shows that TEOS–VTES successfully bonded to Al surface.The 0.64eV shift of Al 2p binding energy indicates a new Si–O–Al bond formed on Al surface.The corrosion protection e?ciencies of the TEOS–VTES-coated aluminum pigments prepared under the optimum experimental conditions reach 99.8%and 99.9%in acid media of pH 1and alkaline media of pH 11,respectively,suggesting that TEOS–VTES sol–gel coatings can protect aluminum pigments well in corrosion media.ó2007Elsevier Ltd.All rights reserved.

Keywords:A.Aluminum;C.Acid and alkaline corrosion;B.FTIR;B.SEM;B.XPS

1.Introduction

Lamellar aluminum pigments (‘‘aluminum ?akes ”)have been used in solvent-borne metallic paints or inks for many years [1]due to their metallic appearance and ‘‘?op-e?ect ”[2].Recently,growing importance of environmental aspects has led the paint and coatings industry to the development of coating systems with a reduced content of volatile organic compounds (VOC)[2,3].Waterborne coatings are the preferred way to solve the problem.However,the alu-minum pigments can react with water:2Al t6H 2O ?2Al eOH T3t3H 2

This results in severe deterioration of metallic luster and dangerous pressure build up in the storage vessels [1–7].

The methods adopted for aluminum pigments stabilization in aqueous media can be divided into two principal catego-ries [8]:the adsorption of corrosion inhibitors on the pig-ment surface [1,3–7,9–18]and the encapsulation of the pigment with a protective coating [2,8,19–22].The encapsu-lation method is more promising since the protective layer can insulate the aluminum pigments from the corrosion medium.Inorganic coatings,such as SiO 2,show excellent mechanical strength,but poor compatibility with resins and other organic compounds contained in waterborne coatings.In regard to organic coatings,the poor adhesion of the coating material to the aluminum surface greatly lim-its their application.The combination of inorganic and or-ganic compounds for the encapsulation of the aluminum pigments may be more e?ective and promising,but few re-ports can be found in this ?eld till now.Furthermore,up to now,the long-term stability of aluminum pigments in acid or alkaline media has not been solved completely.

The sol–gel process,involving the hydrolysis and con-densation of the alkoxides (typically tetraethoxysilane

0010-938X/$-see front matter ó2007Elsevier Ltd.All rights reserved.doi:10.1016/j.corsci.2007.11.002

*

Corresponding author.Tel.:+862087112057807;fax:+862087112057804.

E-mail addresses:lilijunscut@https://www.360docs.net/doc/d77531868.html, ,lilijunscut@https://www.360docs.net/doc/d77531868.html, (L.Li).

https://www.360docs.net/doc/d77531868.html,/locate/corsci

Available online at https://www.360docs.net/doc/d77531868.html,

Corrosion Science 50(2008)

795–803

(TEOS)),has been used for corrosion protection of alumi-num[3,8]by the formation of the sol–gel?lm as a barrier layer on the aluminum surface.Silane coupling agents can be incorporated into the sol–gel network to enhance the adhesion between the inorganic surface and the organic compound.One of the well-known silane coupling agents is vinyltriethoxysilane(VTES),which can readily react with other alkoxides to form hybrid inorganic/organic polymers [23].The hybrid inorganic/organic coatings may improve the corrosion resistance of aluminum pigments in acid or alkaline media,and at the same time,enhance the compat-ibility between aluminum surface and other organic com-pounds contained in waterborne coatings.

In this paper,aluminum pigments encapsulated by TEOS and VTES in sol–gel process were reported.Reac-tion conditions were analyzed and optimized to obtain the encapsulated aluminum pigments with excellent stabil-ity in acid and alkaline media.

2.Experimental

2.1.Materials

Raw materials used are listed in Table1.Aluminum pig-ments(median particle size of30l m)were washed with ethanol and distilled water before encapsulation,then dried under vacuum at50°C.TEOS and VTES were puri?ed by distillation prior to use.Absolute ethanol and ammonia solution were used as received without further puri?cation.

2.2.Encapsulation

Two grams of aluminum pigments and50ml of ethanol were put into a four-neck round bottom?ask connected to a condenser,thermometer,and nitrogen gas inlet/outlet. The solution was stirred at room temperature for1h and then heated to a certain temperature(30–70°C).Ammonia (1.5–9ml)and distilled water(2.5–12.5ml)diluted with 30ml ethanol,TEOS(2or3ml)and VTES(1–3ml)also diluted with30ml ethanol,were added drop-by-drop over a period of1h to the solution simultaneously.The solution was further stirred for6h,and then?ltered and the residue washed with ethanol.The resulting pigments were dried under vacuum at60°C for5h.The speci?cation of prepar-ing conditions used in our experiment was listed in Table2.

2.3.Characterization

Fourier transformation infrared(FTIR)measurements were carried out by using a Bruker Vector33spectrometer to characterize the functional groups of the pigments.The samples were ground with dried potassium bromide(KBr) powder,and compressed into a disc.The KBr disc was sub-jected to analysis by an IR spectrophotometer.The scan-ning electron microscopy(SEM)investigations were performed with a Philips FEI XL-30ESEM.X-ray photo-electron spectroscopy(XPS)spectra were obtained on a Kratos Axis Ultra(DLD)photoelectron spectrophotome-ter with a monochromatic Al K a source(1486.6eV).Each analysis started with a survey scan from0to1100eV,pass energy of160eV at steps of1eV.For the high resolution analysis,the pass energy was lowered to40eV at steps of 100meV.The binding energy scale was calibrated from the carbon contamination using the C1s line(285.0eV).

To evaluate the e?ect of the encapsulation described in this paper,the stability test was carried out.0.1g of the encapsulated or unencapsulated aluminum pigments were dispersed in H2SO4solutions of pH1for stability test in acid media and in NaOH solutions of pH11for stability test in alkaline media respectively.The suspension was put in60ml glass bottles and stored at room temperature for720h.The hydrogen evolved was collected to estimate the e?ect of the encapsulation.The corrosion protection e?ciency(P,%)was calculated using the following equation:

P?

V unencàV enc

V unenc

?100%

where the V unenc and V enc are the evolved hydrogen volume of the unencapsulated and encapsulated aluminum pig-ments in the stability tests,respectively.

3.Results and discussion

3.1.Encapsulation process

The?owchart for preparation of aluminum pigments was given in Fig.1.The ethoxy groups of the TEOS and VTES hydrolyze and condense in the ethanol/water media under catalysis by the ammonia solution.On the other hand,there is a layer of aluminum oxide on the surface of the aluminum pigments due to their exposure to the air.The surface of the aluminum oxide layer in a humid or moist environment has a signi?cant population of hydroxyl groups[24].These surface hydroxyls can partici-pate in the sol–gel condensation reaction of the TEOS and VTES to form a chemical linkage,Si–O–Al,between the aluminum and the silicon sol–gel?lm.This chemical bond formation produces the strong interaction of the sol–gel layer with the aluminum surface.

Table1

Raw materials

Materials Grade Manufacturer

Aluminum

pigments P99%,Tianlong Trade Co.,Ltd.à30l m

Absolute ethanol P99.5%Union Chemical Industry Reagent

Research Institute

Ammonia solution25–28%a Donghong Chemical Co.,Ltd. Tetraethoxysilane P28.5%b Guanghua Chemical Co.,Ltd. Vinyltriethoxysilane P98%Kete Fine Chemical Industry Co.,Ltd.

a NH

3content.

b SiO

2content.

796L.Li et al./Corrosion Science50(2008)795–803

3.2.Optimization of reaction parameters

3.2.1.E?ect of the ratio of VTES/TEOS

The di?erence between the rates of hydrolysis and con-densation of di?erent precursors will lead to the morphol-ogy and property diversity of the coatings.The SEM micrographs of aluminum pigments encapsulated at varied ratios of VTES/TEOS are shown in Fig.2.For compari-son,the SEM micrograph of uncoated aluminum pigments is also given.From Fig.2a–g,it can be found that when the volume of TEOS is nearly constant(2or3ml),the increase of the ratio of VTES/TEOS results in increase of netlike polymer?lms on the surface of aluminum pigments.Typi-cally,when the volume ratio of VTES/TEOS is3/2 (Fig.2d),the coatings seem dense,indicating best barrier layers formed for corrosion protection of aluminum pigments.

Further comparison of di?erent samples in acid aqueous media of pH1is shown in Fig.3.It can be seen that when the volume of TEOS is2ml,the stability of encapsulated aluminum pigments increases with the content of VTES. However,when the volume of TEOS is3ml,opposite con-clusion can be drawn.This may result from hydrophobicity and compactness of the sol–gel?lms.Increasing the rela-tive amounts of organic component will increase the hydro-phobicity of the?lm and therefore lead to a better barrier layer.On the other hand,when the amounts of silane increase,water becomes the limiting factor,resulting in ine?cient hydrolysis and condensation reactions.As a result,the coatings on aluminum pigment surface are loose and can not provide enough corrosion protection.From Fig.3,aluminum pigments encapsulated at the ratio of VTES/TEOS=3/2show best stability in acid media of pH1,which is consistent with the result of SEM measurement.

3.2.2.E?ect of reaction temperature

As seen from Fig.4,reaction temperature has great in?uence on the stability of encapsulated aluminum pig-ments in acid media.When the temperature is50°C,the encapsulated pigments exhibit best stability.It is because the rates of hydrolysis and condensation of silane depend on reaction temperature.It was reported that under basic condition,the condensation of siloxane is much faster than the hydrolysis and the condensation species participate in nucleation at once and retain a very low concentration [25].When the reaction temperature is low,the rate of hydrolysis is much slower than that of condensation,which indicates that the condensation species participate in nucle-ation as soon as silanol comes into being.As a result,par-ticles in stead of uniform?lms are formed on the surface of aluminum pigments,which induces unfavorable barrier layer.On the contrary,the high reaction temperature will result in high nucleation rate.Consequently,the barrier

Table2

Speci?cation of preparing conditions in the experiment

No.Reaction

temperature(°C)Mass of aluminum

pigments(g)

Volume of

ethanol(ml)

Volume of

TEOS(ml)

Volume of

VTES(ml)

Volume of

ammonia(ml)

Volume of

water(ml)

1#200000

2#4021102135

3#4021102235

4#4021102335

5#4021103135

6#4021103235

7#4021103335

8#3021102235

9#5021102235

10#6021102235

11#7021102235

12#40211022 1.55

13#4021102265

14#4021102295

15#402110223 2.5

16#4021102237.5

17#40211022310

18#40211022312.5

19#5021102335

20#5021102365

L.Li et al./Corrosion Science50(2008)795–803797

layer is not compact because the amount of silanol absorbed on the aluminum surface decreases.In our exper-iment,50°C is the optimum temperature for encapsulation of aluminum pigments.

3.2.3.E?ect of ammonia

Ammonia was used as a catalyst in the sol–gel process.The concentration of ammonia has also great in?uence on the rate of hydrolysis and condensation of silane.When the concentration of ammonia increases,the rate of hydro-lysis and condensation of silane also increases,which is favorable for encapsulation of aluminum (Fig.5).How-ever,high concentration of ammonia will increase the ionic strength of the solution,which may induce aggregation of aluminum pigments.Therefore,high concentration of ammonia is unfavorable for formation of compact

?lm

Fig.2.SEM micrographs of aluminum pigments encapsulated at di?erent ratio of VTES/TEOS:(a)1#;(b)2#;(c)3#;(d)4#;(e)5#;(f)6#;and (g)7#.

798L.Li et al./Corrosion Science 50(2008)795–803

on the aluminum surface.When the volume of ammonia is 6ml,the encapsulated aluminum pigments exhibit best sta-bility in acid aqueous media of pH 1.

3.2.

4.E?ect of water

When the amount of silane and ammonia is kept con-stant,increasing the amounts of water will greatly promote the rate of hydrolysis.However,the concentration of silane in the system will be reduced signi?cantly when the amount of water is increased,which reduces the hydrolysis and con-densation reactions [26].From Fig.6,we can ?nd that when the volume of water is 10ml,the encapsulated alumi-num pigments display best stability in acid media.

3.2.5.Aluminum pigments encapsulated under optimized conditions

The SEM micrographs of the aluminum pigments pre-pared under optimized conditions were shown in Fig.7.From Fig.7,we can ?nd that the ?lms formed on the sur-face of aluminum pigments are much denser than those shown in Fig.2.Results of stability test of these samples are shown in Fig.8.For direct and clear comparison,the stability of uncoated aluminum pigments is also given.From Fig.8,it can be found that the aluminum pigments prepared under optimized conditions exhibit excellent sta-bility both in acid and alkaline media.The corrosion pro-tection e?ciencies of 19#and 20#samples reach 99.8%and 99.1%,respectively in acid media of pH 1.In alkaline media of pH 11,the corrosion protection e?ciencies of 19#and 20#samples are 99.9%and 99.8%respectively.The results of stability test reveal that using TEOS and VTES as precursors in the sol–gel process can provide aluminum pigments su?cient protection in acid and alkaline media.3.3.FTIR analysis

The FTIR spectra of pure VTES,SiO 2,TEOS-coated Al pigments (TEOS/Al),VTES-coated Al pigments (VTES/

L.Li et al./Corrosion Science 50(2008)795–803

799

Al),and TEOS–VTES-coated Al pigments (TEOS–VTES/Al)(19#),are shown in Fig.9.Table 3lists the analyzed FTIR absorption peaks and the corresponding https://www.360docs.net/doc/d77531868.html,paring Fig.9a and d,vibration bands for vinyl group at near 3061cm à1,1407cm à1,760cm à1and 547cm à1are

clearly shown in Fig.9a,which can be also found in the spectrum of VTES/Al,indicating the existence of VTES on the surface of Al pigments.In addition,the characteristic peaks near 2977cm à1,2929cm à1,2887cm à1,1296cm à1and 1168cm à1are assigned to the vibration of ethoxy group,which disappear in spectra of VTES/Al,suggesting the reaction of ethoxy group in the process.In the spectrum of VTES/Al,the new absorption peaks appearing near 3440cm à1and 950cm à1can be attributed to Si–OH asymmetric stretch and Si–OH stretch respectively,which demonstrates that ethoxy group of VTES hydrolyzed in the sol–gel reaction.The bands near 1120cm à1,950cm à1,799cm à1and 625cm à1are assigned to the vibration of Si–O–Si,indicating that the Si–OH or Si–OC 2H 5further condensed in the sol–gel https://www.360docs.net/doc/d77531868.html,-paring Fig.9b and c,the absorption bands of SiO 2can also be found in the spectrum of TEOS/Al,which means that the SiO 2exists on the Al surface.As seen from Fig.9c–e and Table 3,the Si–O–Si asymmetric stretch bands appear near 1120and 1100cm à1in the spectra of VTES/Al and TEOS/Al respectively.However,in the spectra of TEOS–VTES/Al,two absorption bands near 1094cm à1and 1133cm à1appear,which suggests that TEOS and VTES may react each other in the sol–gel

process.

Fig.7.SEM micrographs of aluminum pigments encapsulated under optimum conditions:(a)19#;(b)20#.

800L.Li et al./Corrosion Science 50(2008)795–803

3.4.XPS analysis

Figs.10and 11present the results of XPS measurements for further quantitative analysis of the elements on the sur-face of aluminum ?akes and chemical states of the ele-ments.The spectrum of the bare Al ?akes (Fig.10a)shows signals due to the presence of oxygen (531.32eV,O 1s);carbon (284.32eV,C 1s)and aluminum atoms (73.32eV,Al 2p)[34].The characteristic peaks of Si 2s and Si 2p in Fig.10b (19#)manifest that the presence of Si element on the surface of the particles is evident,which suggests that TEOS and VTES have been successfully bonded onto the surface of aluminum pigments.The spec-i?cation of the elemental contents on the surface of the alu-minum pigments is listed in Table 4.From Table 4,it is found that the atomic ratio of O/Si (à1.92)is between the O/Si (à2)of TEOS condensate and the O/Si (à1.5)of VTES condensate.It suggests that both TEOS and VTES occupied the surface of Al,which is consistent with the SEM observation.

Fig.11a and b shows the XPS spectra of the O 1s and Al 2p on the surface of Al.It is seen that O 1s peak appears at

Table 3

Assignment of the FTIR peaks and corresponding references VTES

SiO 2VTES/Al TEOS/Al VTES–TEOS /Al

Assignment

References Peak positions (cm à1)

3448

3440

3428

3430Si–OH asymmetric stretch [27,28]30613066

Vinyl CH 2asymmetric stretch [29]2977CH 3symmetric stretch

[29]2929Ethoxy CH 2asymmetric stretch [29]2887CH 3symmetric stretch [29]16341637163316341639H–O–H

[30]

1599C @C stretch

[28,29,31]14071407Vinyl CH 2in-plane def.[29,30]1296Ethoxy CH 2twist

[29]12761277

Vinyl CH.in-plane bend [29,30]1168C–C stretch

[29]

1087112011001133,1094

Si–O–Si asymmetric stretch [28–30,32]1105Si–O stretch [29]1082Si–O stretch [29]1011Vinyl CH 2rock [29]962

Vinyl CH 2wag [29,31]966950

951Si–OH stretch

[27,28,33]799

799

Si–O–Si symmetric stretch [28,33]786Si–C stretch [29]760

763

Si–C stretch

[29]625

Si–O–Si bending vibration [29]547549

Vinyl C–H bending vibration [29,30]468

Ethoxy C–C–O def.

[29]466

465

466

Si–O–Si bending vibration

[28,33]

L.Li et al./Corrosion Science 50(2008)795–803

801

532.01eV induced by Al2O3[35]on the uncoated Al sur-face.However,the O1s peak of TEOS–VTES/Al changes to532.89eV,originated mainly from TEOS and VTES [27],which also manifests that TEOS and VTES encapsu-lated aluminum pigments.As seen from Fig.11b,the Al 2p peak shows a chemical shift from74.13eV to 74.77eV.In general a chemical shift is caused by changes in the electrostatic potential?eld experienced by the core electrons.It’s well known that less than0.5eV shift is in the range of the typical precision of the XPS instrument. In addition,J.Theo Kloprogge[35]reported that for Al2O3high resolution Al2p scans showed no signi?cant changes in binding energy,with all values between73.9 and74.4eV.Therefore,the0.64eV shift of Al2p binding energy indicates a new Si–O–Al bond formed on Al surface.

4.Conclusion

The investigation shows that TEOS and VTES can be used as precursors in the sol–gel process to form a dense protecting layer on the surface of aluminum pigments.It was found that ratio of VTES/TEOS,reaction tempera-ture,contents of ammonia and water have great in?uence on the sol–gel?lm forming on the surface of aluminum pig-ments and thus on the stability of the encapsulated pig-ments in corrosion media.The corrosion protection e?ciencies of the TEOS–VTES-coated aluminum pigments prepared under the optimum experimental conditions reach99.8%and99.9%in acid media of pH1and alkaline media of pH11,respectively,suggesting that TEOS–VTES sol–gel coatings can protect aluminum pigments well in corrosion media.The FTIR analysis indicates that both TEOS and VTES hydrolyzed and consequently condensed in the sol–gel reaction.The shift of Si–O–Si absorption band in the FTIR measurements suggests that TEOS reacted with VTES in the sol–gel process.It was found from SEM analysis that the TEOS–VTES formed a dense netlike layer on the aluminum surface.The XPS result indi-cates that TEOS and VTES bonded to aluminum surface and a new Si–O–Al bond may form in the process. Acknowledgments

The work has been?nancially supported by the project of the Guangdong Provincial Natural Science Foundation of China(07006528).The authors are grateful for the sup-port of Miss Shu-yi Zhu,Mr.Yang(for SEM),Mr.Jiang (for FTIR)and Mr.Yin(for XPS)for their experimental and measurement contributions.

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Elemental contents on the surface of Aluminum pigments

Sample Elemental content(%)

Si Al O C

Uncoated Al026.09422.10151.805

TEOS–VTES/Al20.2149.68638.72931.371

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六级单词解析造句记忆MNO

M A: Has the case been closed yet? B: No, the magistrate still needs to decide the outcome. magistrate n.地方行政官,地方法官,治安官 A: I am unable to read the small print in the book. B: It seems you need to magnify it. magnify vt.1.放大,扩大;2.夸大,夸张 A: That was a terrible storm. B: Indeed, but it is too early to determine the magnitude of the damage. magnitude n.1.重要性,重大;2.巨大,广大 A: A young fair maiden like you shouldn’t be single. B: That is because I am a young fair independent maiden. maiden n.少女,年轻姑娘,未婚女子 a.首次的,初次的 A: You look majestic sitting on that high chair. B: Yes, I am pretending to be the king! majestic a.雄伟的,壮丽的,庄严的,高贵的 A: Please cook me dinner now. B: Yes, your majesty, I’m at your service. majesty n.1.[M-]陛下(对帝王,王后的尊称);2.雄伟,壮丽,庄严 A: Doctor, I traveled to Africa and I think I caught malaria. B: Did you take any medicine as a precaution? malaria n.疟疾 A: I hate you! B: Why are you so full of malice? malice n.恶意,怨恨 A: I’m afraid that the test results have come back and your lump is malignant. B: That means it’s serious, doesn’t it, doctor? malignant a.1.恶性的,致命的;2.恶意的,恶毒的 A: I’m going shopping in the mall this afternoon, want to join me? B: No, thanks, I have plans already. mall n.(由许多商店组成的)购物中心 A: That child looks very unhealthy. B: Yes, he does not have enough to eat. He is suffering from malnutrition.

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图1 DDM仿真软件模块结 ①如果将三维实体定义为零件,可以自动获得其质量特性。 ②如果用其他图素定义零件,则可人工设定质量特性。 5)可以定义各种铰链铰链用于连接发生装配关系的各个零件,系统提供六种基本铰链和两种特殊铰链。 基本铰链: ①旋转铰——沿一根轴旋转。 ②平移铰——沿一根轴移动。 ③旋转滑动铰——沿一根轴旋转和移动。 ④平面铰——在一个平面内移动并可沿平面法线旋转。 ⑤球铰——以一点为球心旋转。 ⑥十字铰——沿两根垂直轴旋转。 特殊铰链:

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base on的例句

意见应以事实为根据. 3 来自辞典例句 192. The bombers swooped ( down ) onthe air base. 轰炸机 突袭 空军基地. 来自辞典例句 193. He mounted their engines on a rubber base. 他把他们的发动机装在一个橡胶垫座上. 14 来自辞典例句 194. The column stands on a narrow base. 柱子竖立在狭窄的地基上. 14 来自辞典例句 195. When one stretched it, it looked like grey flakes on the carvas base. 你要是把它摊直, 看上去就象好一些灰色的粉片落在帆布底子上. 18 来自辞典例句 196. Economic growth and human well - being depend on the natural resource base that supports all living systems. 经济增长和人类的福利依赖于支持所有生命系统的自然资源. 12 1 来自辞典例句 197. The base was just a smudge onthe untouched hundred - mile coast of Manila Bay. 那基地只是马尼拉湾一百英里长安然无恙的海岸线上一个硝烟滚滚的污点. 6 来自辞典例句 198. You can't base an operation on the presumption that miracles are going to happen. 你不能把行动计划建筑在可能出现奇迹的假想基础上.

用ModelSimSE进行功能仿真和时序仿真的方法(ALTERA篇)

用ModelSimSE进行 功能仿真和时序仿真的方法 (ALTERA篇) 黄俊 April 2007

用ModelSim SE进行功能仿真和时序仿真的方法 (ALTERA篇) 软件准备 (1) QuartusII,本文截图是QuartusII 6.1界面的。我个人认为,如果是开发StratixII或CycloneII或MAXII,用QuartusII6.0+SP1+SP2比较稳定。 (2) ModelSim SE. ALTERA仿真库要已经装好,安装仿真库的笔记已记录于《在ModelSimSE中添加ALTERA仿真库的详细步骤》中。我电脑上装的是ModelSim SE 6.1b。 例子程序的制作 先在Quartus II里生成一个例子程序,以方便介绍三种仿真的方法。步骤如下: 1、新建一个工程(Project),工程名取lpm_shift, 器件选CycloneII EP2C5Q208C, 第三方 的工具暂时都不选。 2、菜单栏上Tools?MegaWizard Plug-In Manager, 点Next,在storage中选 LPM_SHIFTREG,输出文件格式根据习惯选一种语言,在这里以Verilog的为例,在右边的output file名字中加上lpm_shift。点Next。

3、这个例子是做一个移位寄存器,调用lpm库,和cycloneII元件库,也正好可以作为对 前面建好的ALTERA库的一个验证。点可以查到该模块的使用说明和详细介绍。移位寄存器比较简单,就不用细看了。如下图设置.点Next.

4、加上一个异步清零端,点Next,再点Next,最后点Finish. Add/Remove Files in Project…,

英语造句大全

英语造句大全English sentence 在句子中,更好的记忆单词! 1、(1)、able adj. 能 句子:We are able to live under the sea in the future. (2)、ability n. 能力 句子:Most school care for children of different abilities. (3)、enable v. 使。。。能句子:This pass enables me to travel half-price on trains. 2、(1)、accurate adj. 精确的句子:We must have the accurate calculation. (2)、accurately adv. 精确地 句子:His calculation is accurately. 3、(1)、act v. 扮演 句子:He act the interesting character. (2)、actor n. 演员 句子:He was a famous actor. (3)、actress n. 女演员 句子:She was a famous actress. (4)、active adj. 积极的 句子:He is an active boy. 4、add v. 加 句子:He adds a little sugar in the milk. 5、advantage n. 优势 句子:His advantage is fight. 6、age 年龄n. 句子:His age is 15. 7、amusing 娱人的adj. 句子:This story is amusing. 8、angry 生气的adj. 句子:He is angry. 9、America 美国n.

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