Laser Coating of Composites for Enhanced Wear and Corrosion Resistance
Abstract
A new technique has been developed to produce glassy surface coatings on Metal Matrix Composites (MMCs) based on laser induced chemical reduction of metal salts. The substrate is first coated with a paste containing concentrated salts of the elements to be coated (ex. nickel formate, cobalt acetate, phosphorous, etc.) along with a thickening agent. The rise in the surface temperatures during laser irradiation will lead to the decomposition of salts to their native metals. The combination of these metal and metalloid elements in the reaction zone form an amorphous layer due to the specific chemical ratio and rapid cooling rate. The thickness of the coatings obtained were on the order of 50-100 microns, exhibited amorphous and microcrystalline structures, possessed hardness in the range of 300-1700 HV (substrate hardness 80-90 HV), and had superior. sliding wear resistance and excellent corrosion resistance. The formation of glassy surface coatings depends on the specific ratio of the metal- metal or metal-metalloids in the surface layers. The advantages of this process include the formation of glassy coatings on MMCs by a simple, versatile, technique which does not require any vacuum or inert atmospheres.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 28, 1992
- Accession Number
- ADA249231
Entities
People
- Arul Molian
- Madhav R. Govindaraju
- P. Molian