Improving tribological properties of cast Al-Si alloys through application of w...

• Author(s): Culliton, David ; Betts, Anthony ; Carvalho, S. ; Kennedy, David
• Date: 2013
• Persistent ID: http://hdl.handle.net/1822/27594
• Origin: RepositóriUM - Universidade do Minho
• Subject(s): Hardness; Microscale abrasion; Non-ferrous metals; Thermal spray coatings; Three-body abrasion; Two-body abrasion
• Document Type: Article
• Language: English

Description

Flame Spray Thermal Spray coatings are low-cost, high-wear surface-treatment technologies. However, little has been reported on their potential effects on cast automotive aluminum alloys. The aim of this research was to investigate the tribological properties of as-sprayed NiCrBSi and WC/12Co Flame Spray coatings applied to two cast aluminum alloys: high-copper LM24 (AlSi8Cu3Fe), and low-copper LM25 (AlSi7Mg). Potential interactions between the mechanical properties of the substrate and the deposited coatings were deemed to be significant. Microstructural, microhardness, friction, and wear (pin-on-disk, microabrasion, Taber abrasion, etc.) results are reported, and the performance differences between coatings on the different substrates were noted. The coefficient of friction was reduced from 0.69-0.72 to 0.12-0.35. Wear (pin-on-disk) was reduced by a factor of 103-104, which was related to the high surface roughness of the coatings. Microabrasion wear was dependent on coating hardness and applied load. Taber abrasion results showed a strong dependency on the substrate, coating morphology, and homogeneity.