不同基体高铝青铜等离子喷焊层组织与摩擦磨损机理

Microstructure and Wear Behaviors of Plasma Spray Welded High Al Bronze Coatings on Different Substrates

采用等离子喷焊技术在不同基体上制备耐磨高铝青铜喷焊涂层,研究喷焊层与基体之间元素扩散对喷焊层组织的影响,并在室温条件下采用销-盘式摩擦磨损试验机考察喷焊层的摩擦磨损性能,进而分析喷焊层的磨损机理.结果表明:三种基体喷焊层在干摩擦条件下摩擦磨损机理存在明显差异,45钢基体喷焊层中团聚状k相易与对摩件发生黏着,脱落成为磨粒,导致严重的磨粒磨损,摩擦系数大;ZQAl9-4铝青铜基体喷焊层中脆性共晶组织(α+γ2)呈网状分布,断裂韧性对材料的磨损起支配作用,主要磨损机制为疲劳磨损与磨粒磨损;T3紫铜基体喷焊层中k相呈细小梅花状,均匀分布在固溶度较大的β'相中,涂层抵抗弹性变形能力提高,疲劳磨损机制得到抑制,摩擦系数小.

High Al bronze coatings was fabricated on different substrates by plasma spray welding.A pin-on-disk wear machine was employed to investigate the element diffusion effects on coating microstructures and its tribological properties.Results indicate that the wear and friction properties of coatings on different substrates were different under dry sliding.Abrasive and adhesive wear on the high Al bronze coating on 45 carbon steel substrate had high friction coefficient beacuse of strong adhesion between k phases and Fe on the counterpart material.Coating on ZQAl9-4substrate was composed of a lot of(α + γ2) net-like eutectic phases,which was brittle and decreased the coatings impact toughness.Fatigue and abrasive wear and low wear resistance were observed.However,for the coating on T3 copper substrate,k phases were uniformly distributed in the β ' phase and thus coatings were hardened by the refined coatings microstructure due to high thermal conductivity of T3 copper,which produced low friction coefficient and wear rate.