Yang XU
,
Yaohui GUAN
,
Zhongyu ZHENG
材料科学技术（英文）
The friction and wear properties of plasma-sprayed nanostructured FeS coating were investigated on an MHK-500 friction and wear tester under both oil lubrication and dry friction condition. The microstructure, worn surface morphology and phase composition of the coating were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that the coating was mainly composed of FeS, a small quantity of Fe1-xS and oxide were also found. The coating was formed by small particles of 50~100 nm in size. The thickness of the coating is approximately 150 μm. The friction-reduction and wear-resistance properties of plasma-sprayed nanostructured FeS coating were superior to that of GCr15 steel substrate. Especially under oil lubrication condition, the friction coefficient of nanostructured FeS coating was 50% of that of GCr15 steel, the wear scar widths of the coating were also reduced to nearly 50% of that of GCr15 steel under high load. The failure of the coating was mainly attributed to plastic deformation under both oil lubrication and dry friction condition.
关键词:
Plasma spray
,
spray
,
Nanostructured
,
FeS
,
Frictio
Thuong-Hien LE
,
Young-Hun
,
Seock-Sam KIM
材料科学技术（英文）
The sliding wear behaviors of ZrO2-22 wt pct MgO (MZ) and ZrO2-8 wt pct Y2O3 (YZ) coatings deposited on a cast aluminum alloy with bond layer (NiCrCoAlY) by plasma spray were investigated under dry test conditions at room temperature. Under all load conditions, the wear mechanisms of the MZ and YZ coatings were almost the same. The material transfer and pullout were involved in the wear process of the studied coatings under the test conditions. The wear rate of the MZ coating was less than that of the YZ coating. While increasing the normal load, the wear rates of the MZ and YZ coatings increased. SEM was used to examine the worn surfaces and to elucidate likely wear mechanisms. Energy dispersive X-ray spectroscopy (EDX) analysis of the worn surfaces indicated that material transfer occurred in the direction from the SiC ball to the disk. Fracture toughness had a significant influence on the wear performance of the coatings. It was suggested that the material transfer played an important role in the wear behavior.
关键词:
Plasma spray
,
null
,
null
,
null
Xiancheng ZHANG
,
Jianming GONG
,
Sh
,
ong TU
材料科学技术（英文）
The thermomechanical behavior and the distribution of residual stresses due to thermal spraying of NiCoCrAlY coating were studied by thermomechanical finite element analysis. The effects of phase transformation due to solidifying process of coating particles, thickness and material properties of coating on the residual stresses were discussed. Results showed that residual stress decreases little with the stress relaxation due to the phase transformation. For the substrates with the same thickness, the residual stress increases with the increase in coating thickness. The state of
residual stresses relates to the material properties of coating and substrate closely. The stress-induced failure model of coating is also discussed.
关键词:
Coating
,
null
,
null
,
null
Minh-quy Le
,
Young-hun Chae
,
Seock-sam Kim
材料科学技术（英文）
The sliding wear behaviors of a single layer Al2O3-30 wt pct ZrO2, a double layer Al2O3-30 wt pct ZrO2/Ni-Cr and a single layer Al2O3-13 wt pct TiO2 coating deposited on low carbon steel by plasma spraying were investigated under lubricated conditions with various normal loads. The plastic deformation, detachment and pull out of splats were involved in the wear process of the studied coatings under test conditions. Crack propagation was found in Al2O3-13 wt pct TiO2 under loads of 70 and 100 N and in Al2O3-30 wt pct ZrO2/Ni-Cr under a load of 130 N. While increasing the normal load, the wear rates of Al2O3-30 wt pct ZrO2 and Al2O3-30 wt pct ZrO2/Ni-Cr slightly increased, the wear rate of Al2O3-13 wt pct TiO2 increased rapidly. The results showed that the Ni-Cr bonding layer improved the wear resistance of the coating system even it is relatively thin compared with the outer coating layer. The influence of this bonding layer on wear behavior of the coating increased as increasing the normal load.
关键词:
Coating
,
null
,
null
糜亮
,
周灿旭
,
丁毅
,
马立群
表面技术
doi:10.3969/j.issn.1001-3660.2009.06.010
采用等离子喷涂方法在304不锈钢表面制备了TiO_2、AT40(40%TiO_2,60%Al_2O_3)涂层,研究了涂层对甲基橙的光催化降解性能.采用金相分析方法和扫描电镜(SEM)观察了涂层微观结构,用X射线衍射法分析了涂层的相结构.结果表明:涂层与基体结合紧密,表面的孔隙有利于降解率的提高,锐钛型TiO_2的含量是影响光催化效果的关键,纯TiO_2涂层的降解率高于AT40涂层.
关键词:
等离子喷涂
,
TiO_2涂层
,
AT40涂层
,
光催化降解性能
徐心洁
,
贺毅
,
马东林
,
刘元忠
表面技术
doi:10.3969/j.issn.1001-3660.2010.01.005
采用大气等离子喷涂法在Q235钢上喷涂了常规微米、纳米Al_2O_3-13%TiO_2复合涂层,对2种涂层进行了高温热氧化实验.利用XRD对比分析了2种涂层及其相应粉末的相组成,利用SEM观察了涂层的表面、截面形貌,并运用EDS对2种涂层的组分分布情况进行分析,比较2种涂层的不同结构及热氧化性能,初步探讨了涂层热氧化失效的原因.结果表明:2种粉末在喷涂之后,涂层中的α-Al_2O_3均有所减少,生成了γ-Al_2O_3,金红石TiO_2相转变成了板钛矿型TiO_2相,增加了涂层的内应力,加剧了裂纹的扩展;常规微米涂层中的孔洞细小但密集,纳米涂层中的孔洞较大但不密集,且大部分的气孔都存在于部分熔化区的内部;涂层在喷涂过程中所生成的气孔以及热氧化过程中由于热应力而产生的裂纹是造成涂层失效的直接原因.
关键词:
等离子喷涂
,
Al_2O_3-13％TiO_2
,
热氧化
,
组织
,
性能
