Tribological Characteristics and Wear Features of Powder Tin Bronze with the Addition of Ultrafine Oxides
- PDF / 1,405,706 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 3 Downloads / 193 Views
ological Characteristics and Wear Features of Powder Tin Bronze with the Addition of Ultrafine Oxides L. N. Dyachkova* O.V. Roman Powder Metallurgy Institute, Minsk, 220005 Belarus *e-mail: [email protected] Received March 17, 2020; revised April 24, 2020; accepted April 29, 2020
Abstract—The effect of the introduction of ultrafine particles of alumina, nickel oxides and a mixture of their oxides on the mechanical and tribological properties, structure and wear characteristics of powder tin bronze is studied. The increase in the content of alumina from 2 to 5 wt % leads to a decrease in strength by 1.2– 1.4 times, and from 5 to 10 wt % it does not affect the change in the tensile strength of powder bronze and leads to a slight decrease in the compressive strength. With an increase in the alumina content from 2 to 10%, the coefficient of friction and the wear rate of powder bronze decrease, and the seizure pressure increases. The addition of nickel oxide to alumina promotes the formation of a homogeneous structure, lower porosity and smaller pore size, an increase in strength, a decrease in coefficient of friction of powder bronze from 0.028 to 0.022, by 2.5 times of wear rate, as well as an increase in seizure pressure from 4 to 7.0 MPa. Keywords: powder bronze, oxides, structure, coefficient of friction, wear, wear surfaces DOI: 10.3103/S1068366620040042
INTRODUCTION The production of highly effective antifriction materials can significantly increase the durability of friction units, simplify their design and maintenance, reduce weight, and increase reliability. The most widely used for work under conditions of boundary friction and without lubrication are copperbased powder antifriction materials, which have successfully replaced traditional alloys, i.e. babbit and bronze. Powder antifriction materials based on non-ferrous metals differ in physical and mechanical properties from materials based on iron with better working performance, high thermal conductivity, low coefficient of friction on mating steel surfaces and increased resistance to corrosion when operating in aggressive medium. The feasibility of their use is due to economic necessity, for example, when operating in pair with a complex or expensive mating steel part. In this case, the smallest wear of the mating part in the friction units achieved. To improve the tribological properties of copperbased powder materials, they are alloyed or numerous additives of various phase compositions in different concentrations are introduced. Powder chromium-tin and chromium-nickel-tin bronzes are used for the operation in friction units without liquid lubrication under moderate and heavy operating conditions (tem-
perature up to 100°C, sliding speed up to 35 m/s, pressure up to 6 MPa) in aggressive environments. For parts operating in friction units without liquid lubrication under moderate and heavy operating conditions, the authors of [1] proposed chrome-alloyed powder bronze. An increase in the tribological properties of powder bronze is achieved by introducing s
Data Loading...
