dacromet达克罗技术

d a c r o m

e t达克罗技术 Document serial number【NL89WT-NY98YT-NC8CB-NNUUT-NUT108】

DACROMET 320 is a non-electrolytic water-based thin-film coating for the corrosion protection of articles made from steel, cast iron or other iron metals. The Coating Contains Zinc and aluminium flakes in a chromium binder. The coating is metallic silver in appearance.

DACROTIZING is the process whereby the aqueous dispersion

is applied by cold immersion or spray and is therefore free of any risk of hydrogen embrittlement. The coating thus produced is passivated throughout the film and provides high performance corrosion protection.

CHARACTERISTICS

The corrosion resistance of DACROMENT 320 depends upon the thickness of the coating and is due to the combination of several mechanisms:

A barrier effect due to the tile-like structure of the film, Controlled sacrificial protection of the zinc in relation

to the metal substrate,

The film passivation which reduces the speed at which the zinc and aluminum are consumed.

COATING THICKNESS

Two coating weights are commonly used to meet the automobile industry’s requirements;

Grade A: coating weight > 24 g/m2, average thickness 5 to 7 um

Grade B: coating weight >36 g/m2, average thickness 8 t0 10 um

Greater coating weights may be applied to increase the duration of the corrosion protection.

PROPERTIES

1/No hydrogen embrittlement

When surface preparation is done according to recommended techniques, the non-electrolytic application of the film does not induce hydrogen embrittlement. DACROMET 320 is therefore especially indicated for protecting security parts.

2/Corrosion resistance

DACROMET 320 meet all automobile manufacturer

specifications for the corrosion protection of mechanical

parts. It is also very well suited for numerous other applications such as building, civil engineering, railway equipment…

Salt spray test(ISO 9227):

>600 hours (Grade A) without red rust.

>1000 hours (Grade B) without red rust.

No white rust (zinc corrosion) before 250 hours.

Salt spray test after 8 hour thermal shock at 260℃

Ditto

Cyclical corrosion tests: 3C test

Test method: RENAULT : >10 cycles without red rust

Bimetallic corrosion resistance:

DACROMET 320 behaves very well in contact with aluminium and performs as well as other zinc-based coatings in contact with copper, stainless steel or magnesium.

3/Resistance to automotive fluids:

Standardized test fuel, diesel fuel, motor oil, organic solvents, cooling fluid, brake fluid; no coating alteration (VDA 621-412)

Immersion in brake fluid for 24 hours at 80℃; no coating alteration.

4/Ductility:

Sufficient for elastic deformations of springs, clip

5/Electrical conductivity:

DACROMET 320 is conductive. It allows for use of electrodeposited paints.

6/Heat resistance:

DACROMET 320 is cured at 300℃, thus providing excellent heat resistance.

7/Paintability:

DACROMET 320 may be covered by most organic coatings and in particular, those applied by electrodeposition.

8/Throwing power

The application on parts by cold immersion allows for the total covering of the internal surfaces.

APPLICATION FIELD

When choosing the coating process best suited for a given application, DACROMET 320 may be used in all industrial areas, for all types of metallic parts.

HOMELOGATIONS

DACROMET 320 is specified and used by all automobile manufacturers, and numerous other companies.

宁波金陵喷漆实业有限公司最新引进达克罗涂覆工艺。

适用于多种基材达克罗涂层可以适用于钢、铸铁、铝、及其合金、粉末冶金等多种材料的表面保护。粉末冶金件、铸铁件的电镀比较麻烦。粉末冶金件镀前要进行封孔处理等。处理不好，吸附到微孔内的酸、碱或其分化学溶液会从内到外地腐蚀镀锌层，从而降低镀锌层的耐腐寿命。采用达克罗涂层则不存在这类问题。

生产设备

达克罗应用

达克罗涂覆工艺被列为清洁生产技术，是1999年国家重点保护实用技术推广项目

国家环境保护总局文件环发[1999]185号

达克罗是DACROMET的中文译音，又称锌铬膜、达克锈、达克曼等，在即将发布的我国有关达克罗的标准中称为“锌铬涂层”，其定义为：“将水基锌铬涂料浸涂、刷涂或喷漆于钢铁零件或构建表面，经烘烤形成的以磷片状锌和锌的铬酸盐为主要成份的无机腐蚀涂层。”达克罗技术是由美国人发明的，是一种类似电镀锌的金属涂层处理技术，达克罗涂层外观为均匀的银灰色，涂层中含有80%的薄锌片和铝片，其余为铬酸盐，具有优良的性能，如极强的抗腐蚀性：比电镀锌提高7~10倍；无氧脆；特别适用于高强度受力件，如用于地铁工程的高强度螺栓；高耐热性；耐热温度300℃。此外，还具有高渗透性、高附着性、高减摩性、高耐气候性、高耐化学品稳定性及无环境污染等优点。

达克罗技术工艺处理过程无公害、无环境污染，这是优越于任何一种金属表面

处理工艺的最大特点。在达克罗涂层形成过程中，挥发物质经过汽化处理。不存在含有酸、碱、锌、铬物质的污水排放问题。被国家机械工业定为“清洁生产技术”基金开发项目。被专家誉为国际金属表面处理行业的一场革命性产品。达克罗工艺对于各种类形工件具有广泛的适应性，既可以处理小型零件，如：紧固件、五金配件；也可以处理大型结构和钣金件。达克罗涂层具有良好的工艺配套性，可以在涂层表面进行静电喷粉、喷漆、电泳漆等二次涂覆，以提高金属表面的抗污染性并满足种种产品的表面装饰性。在工业发达国家的汽车，土木建筑，电力、化工、海洋工程、家用电器、铁路、公路、桥梁、隧道、军事工业等众多领域里已经得到极为广泛的应用。为此我公司引进当今国际先进的反腐防锈技术—“达克罗”为各行业提供达克罗涂覆加工优质服务。欢迎各行业人员垂询。

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