涂层-FDA导则

金属等离子喷涂Mechanical Properties - Modified SurfaceCDRH recommends that a statistically adequate number of samples be tested at each load in each test. Generally, five plasma sprayed coating samples will be needed, unless it can be shown that a smaller number of samples can give adequate power of the test and adequate Type I and Type II errors.Either finished devices or surface treated coupon samples processed identically to the final device should be used in the tests below.1.The shear fatigue strength of surface coating should be tested out to at least107 cycles as per ASTM F1160, or a justification for the test method used should be provided, e.g., Pilliar, 1975; or Manley, 1987.2.The static shear strength of the surface/substrate interface should be tested byeither method described in ASTM F-1044. The thermal sprayed coating should exceed 20 MPa in shear strength. (ASTM F 1044, Levine, 1985).3.The static tensile strength of the surface/substrate interface should shall betested by either method described in ASTM F-1147. The coating should exceed 22 MPa in tensile strength. (Levine, 1985; Ducheyne, 1986). Tension may be applied to the modified surface using a polymeric adhesive with a minimum tensile strength of 24.1 MPa (ASTM C 633: Adhesion or Cohesive Strength of Flame-Sprayed Coatings). The properties of the adhesive should be reported.4.The abrasion resistance of the coating should be tested as described in ASTM1978-99. The Taber Abraser should be loaded with an H-22 wheel, use a total load of 250 g-f and each sample should be run for 100 cycles. Samples should have mass loss and cumulative mass loss determinations reported after 2, 5, 10 and 100 cycles. Mass losses should be reported as means with standard deviations. Thermal spray coatings should lose less than a total of 65 mg (by weight) when abraded for 100 cycles.Hydroxyapatite Coated Orthopedic ImplantsCeramic Coating InformationWe recommend that you include the information listed below for an implant coated with a ceramic coating such as hydroxyapatite or calcium phosphate.∙particle size and particle size distribution of the powder used for the coating∙average porosity size for the coating∙overall pore volume for the coating∙identity of the area of the implant to be coated∙scanning electron microscopy pictures at 100X of the coated implant surfaces and of a cross-sectioned area of the device showing the coating interface∙measurements of coating thickness and tolerances∙chemical analysis of the powder before and after coating, including Ca/P ratios in atomic percent and elemental analysis∙total percentage of all crystalline phases in the coating and total percentage of crystalline hydroxyapatite in the coating∙type of deposition process used and the post-deposition treatment∙x-ray diffraction pattern of the powder and the coating in terms of relative intensity versus diffraction angle∙urface roughness of the coating∙abrasion characteristics of the coating, including the abrasion testing methodology.We also recommend that you include static tensile and shear bonding strengths between the coating and the implant surface with testing from 5 or more samples included in the averages. We recommend the following standards, where appropriate to your device’s composition:∙ASTM F1160-98 Standard Test Method for Shear and Bending Fatigue Testing of Calcium Phosphate and Metallic Medical Coatings∙ASTM F1147-99 Standard Test Method for Tension Testing of Calcium Phosphate and Metal Coatings∙ASTM F1501-95 Standard Test Method for Tension Testing of Calcium Phosphate Coatings∙ASTM F1658-95 Standard Test Method for Shear Testing of Calcium Phosphate∙ASTM F1659-95 Standard Test Method for Bending and Shear Testing of Calcium Phosphate Coatings on Solid Metallic SubstratesFor CA phosphate coatings please see ASTM F1609-95 Standard Specification for Calcium Phosphate Coatings for Implantable Materials. For other types of ceramic coatings, ASTM F1501-95 Standard Test Method for Tension Testing of Calcium Phosphate Coatings may be useful in devising your own test method.Metallic Coating InformationWe recommend that you include the information listed below for an implant coated with a metallic coating:∙complete chemical composition of the powder used for the coating and of the coating itself∙coating thickness and porosity∙mean volume percent of voids∙surface roughness of the coating∙identity of the area of the implant to be coated∙scanning electron microscopy pictures at 100X of the coated implant surfaces and of a cross-sectioned area of the device showing the coating interface∙abrasion characteristics of the coating, including the abrasion testing methodology.We also recommend that you include static tensile and shear bonding strengths of the coating to the implant with results from 5 or more samples included in the averages. We recommend the following standards, where appropriate to your device’s composition:∙ASTM F1044-95 Standard Test Method for Shear Testing of Porous Metal Coatings∙ASTM F1147-99 Standard Test Method for Tension Testing of Calcium Phosphate and Metal Coatings∙ASTM F1160-98 Standard Test Method for Shear and Bending Fatigue Testing of Calcium Phosphate and Metallic Medical Coatings∙ASTM F1580-95 Standard Specification for Titanium and Titanium-6% Aluminum-4% Vanadium Alloy Powders for Coating Surgical Implants.Blasted Surfaces InformationWe recommend that you include the information listed below for an implant with a blasted surface:∙identity of any surface treatments that blast the implant∙composition of the particles∙identity of any treatments to remove particles from implant surfaces∙identity of agents used in particle removal∙chemical analysis of the surface to verify that any chemicals used to remove particles have been washed from the surface∙photomicrographs of blasted surfaces to show whether or not there are particles remaining behind on the surface.。