射频反应磁控溅射制备氧化铬薄膜技术及性能

研究了采用射频反应溅射方法制备氧化铬耐磨镀层的技术和薄膜的性能.结果表明,采用金属靶材进行射频反应溅射时,由于靶材与反应气体的反应,会出现两种溅射模式,即金属态溅射和非金属态溅射,非金属态溅射模式的沉积速率很低.氧化铬薄膜的硬度主要决定于薄膜中Cr₂O₃含量,在供氧量不足时会生成低硬度的CrO,制备高硬度氧化铬薄膜需要采用尽可能高的氧流量进行溅射.采用在基片附近局域供氧,可以实现高溅射速率下制备出高硬度的氧化铬薄膜.     

Deposition of immersion coatings on steel tire cord

The deposition of immersion coatings of Cu-Sn alloy from sulfuric-acid solution onto steel tire cord is investigated. The influence of the cord speed in the bath on the alloy’s chemical composition and deposition rate is considered. The concentration of the solution’s basic components is determined, and their influence on the deposition rate and composition of the coating is discussed. The upper limit on the Fe²⁺-ion concentration in the solution is established.     

Deposition of chromium coatings on diamonds from a gaseous phase

Conclusions A thermodynamic analysis of the reaction of diamonds with a gaseous chromium iodide phase has enabled the optimum conditions of coating deposition on diamonds to be determined. It has been established by experiment that treatment for 0.25–1.0 h at temperatures ranging from 700 to 1000°C results in the deposition on diamonds of 0.1- to 2.0-m-thick layers composed of the chromium carbides Cr₇C₃ and Cr₃C₂, Cr₇C₃ being the first to form.Translated from Poroshkovaya Metallurglya, No. 4(232), pp. 46–49, April, 1982.     

Physicomechanical properties and failure of detonation coatings

Conclusions The effect of the complex of external factors such as plastic deformation, temperature, chemical interaction causes structural and phase changes of powder materials in detonation coatings leading to relatively low ductility of the coating. The bend strength of the coatings up to 0.25 mm thick is similar to that of the dense materials. To produce high-quality detonation coatings, it is necessary to avoid hard temperature and kinetic parameters of the spraying process, and the extent of deformation of the particles should be limited to minimize formation, in the coatings, of internal stresses and a defective structure. Coatings made of alloyed steels with a large amount of the hardening phase are especially sensitive to defects.The physicochetnical and mechanical properties of the coatings on the substrates showed the strong mutual effect in the process of formation of the coatings and combined deformation under loading. This fact must be taken into account in selecting coating-substrate pairs for service in the conditions specified in advance.The mechanism of failure of detonation of coatings up to 0.25 mm thick produced by optimum technology in three-point bend loading does not differ from the mechanism of failure of the dense materials. With increasing thickness of the coatings their strength and ductility properties rapidly decrease and the failure mechanism also changes.Translated from Poroshkovaya Metallurgiya, No. 11(299), pp. 88–94, November, 1987.     

Deposition of hardening coatings on hard-alloy tools using solar power plant

Conclusions Short-term surface treatment in the solar furnace greatly increases (1.7–4.5 times) the durability of the curring tools of the T16K6 and VK8 hard alloys with the titanium nitride coatings.The pyrometric method of inspection showed that a temperature gradient forms from the surface into the depth of the specimen. The experimental procedure made it possible to determine the correlation between the changes in the composition (the intensification of the diffusion processes), structure, and the variation of the normal spectral emissivity of the hard alloy.In the T15K6 alloys diffusion of carbon from the substrate into the coating is considerably more intense than in the VK8 alloys. This can be explained by the wider range of homogeneity of the carbides included in the composition of the hard alloys of the TK type.Translated from Poroshkovaya Metallurgiya, No. 1(313), pp. 75–80, January, 1989.     

Mechanical properties of spark-deposited restoration coatings

Powder Metallurgy and Metal Ceramics - The hardness, wear resistance, and internal stresses of spark-deposited iron-based coatings are determined. The slower deposition at greater spark discharge...     

Preparation of Al-based amorphous coatings and their properties

Al₈₆Ni₈Co₁La₁Y₂Gd₂ amorphous coatings were prepared using cold gas kinetic spray technology.The results show that Al₈₆Ni₈Co₁La₁Y₂Gd₂ amorphous coatings are achieved with the porosity about 3.2%,thickness about 893 μm,the amount of amorphous phase about 82.5%,the hardness about 300 HV0.2.The corrosion potential and anti-corrosion life of 7075 T6 alloy aluminum are about-0.78 V and 72 h,respectively.The electrochemical analysis and neutral salt spray are about-0.69 V corrosion potential and 274 h anti-corrosion life for amorphous Al-based coatings,respectively.Therefore,the life of the Albased amorphous coatings is about 3.8 times that of 7075 T6 aluminum alloy.Besides,the failure mechanism was analyzed using TEM in this investigation.In a word,Al₈₆Ni₈Co₁La₁Y₂Gd₂ coatings keep dense structure,high amorphous content,favorable amorphous phase stabilizing ability and longer anticorrosion life.That is,Al₈₆Ni₈Co₁La₁Y₂Gd₂ coatings have better comprehensive properties.Therefore,these findings indicate that the present Al₈₆Ni₈Co₁La₁Y₂Gd₂ amorphous coatings prepared using cold gas kinetic spray technique can protect aluminum alloy very well and they can be considered to be used in aviation field.     

Structure and properties of chromium-carbide composite materials and coatings

Conclusions Eutectic chromium-carbide composites show promise as materials for coatings applied by the plasma spray-deposition technique. Use of composite powdered mixtures of chromium and carbides enables coatings to be obtained having phase compositions identical with those of cast alloys. The plasma spray-deposited Cr-TiC, Cr-TaC, and Cr-NbC coatings investigated were found to be superior in wear resistance to sintered alloys of the same compositions and to both cast and plasma spray-deposited chromium. The chromium-carbide composite coatings retained their good wear resistance up to 1000°C. The best results were obtained with Cr-11% TiC and Cr-27% TaC materials. Coatings of this type would appear to be particularly suitable for service under conditions of high-temperature wear in an oxidizing atmosphere, such as are encountered in metallurgical and power generating installations and gas turbine engines.Translated from Poroshkovaya Metallurgiya, No. 11(227), pp. 74–80, November, 1981.     

电沉积Ni-W-WC复合镀层摩擦磨损性能

为了提高Ni-W合金镀层的硬度,改善其耐磨性,在镀层中添加WC颗粒作为硬质相,采用乙醇作为分散剂,利用超声波分散和机械搅拌相结合使WC颗粒均匀地分散于镀液中. 初步探究WC的添加量对镀层硬度及耐磨性能的影响. 结果表明:其他工艺条件不变的情况下,在一定范围内添加WC颗粒,可以较大幅度地提高镀层的硬度及耐磨性;WC添加量为1 g/L时,镀层的综合力学性能最好.