Analysis of a steel disk surface running in tandem with the metal–ceramic friction material MK-5 under the conditions of boundary friction of a hydromechanical transmission

The role of transfer film on high temperature wear properties of a multiphase composite for a brake friction material was investigated using a pad-on-disk type tribometer. A novolac resin-bonded composite based on a simple formulation with 6 ingredients (aramid pulp, cashew dust, Cu fiber, graphite, potassium titanate, and zirconium silicate) was used in this study. Results showed that the wear properties of the composite were significantly affected by the temperature at the frictioninterface when the transfer film was present on the counter face during sliding. In particular, the transfer film on the disk surface was well developed at approximately 200°C, resulting in theimproved wear resistance. It suggested that the transfer film on the disk surface effectively prevented direct contacts of the composite onto the counterface. On the other hand, no apparent relationship between transfer film thickness and friction coefficient was found in this experiment.

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Regularities of the influence of submicron ceramic powders TiO2, AlN, Cr2O3 on the tribological properties of a friction material

PROBLEMS OF TRIBOLOGY ◽

10.31891/2079-1372-2021-99-1-20-27 ◽

2021 ◽

Vol 99 (1) ◽

pp. 20-27

Author(s):

A. Leshok ◽

◽

A. Dykha ◽

Keyword(s):

Friction Coefficient ◽

Friction Material ◽

Metallic Phase ◽

Boundary Friction ◽

Powder Materials ◽

Frictional Material ◽

Friction Materials ◽

Composition Materials ◽

Friction Assemblies ◽

Experimental And Theoretical Studies

Friction units for automotive and special vehicles are designed to operate under boundary friction conditions. Modern vehicles contain friction assemblies that use friction materials. Currently, friction materials are actively used: based on thermosetting resins; pulp and paper-based materials; sintered powder materials; materials of carbon or carbon composition; materials with a ceramic matrix. The development of a unified understanding of the effect of the size and chemical nature of ceramic additives on the processes occurring in a friction material during friction is very important and can be obtained both on the basis of experimental and theoretical studies. The paper presents the results of a study of the effect of submicron TiO2, Cr2O3, AlN powders with a size of 0.2-0.5 microns on the tribotechnical properties of a frictional material based on copper intended for operation under boundary friction conditions. It was found that when using the addition of Cr2O3 powder, the greatest increase in the value of the friction coefficient is noted - from 0.042 to 0.082, a slightly smaller increase in the friction coefficient is shown by the use of AlN and TiO2 defects - 0.042-0.074 and 0.042-0.060, respectively. The least wear of the friction material was obtained when using 3.0 vol. % aluminum nitride additive - 2.1 microns / km. Increasing the addition of any of the submicron powders by more than 7 vol. % leads to a significant decrease in wear resistance. This is due to the formation on the surface of the friction material of a modified layer containing ceramic particles and the metallic phase of the friction material. For the friction material, an unstable value of the friction coefficient and increased wear were recorded

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Analytical and High-Resolution EM Study of Crystalline Phases formed at Metal-Ceramic Interface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100135733 ◽

1990 ◽

Vol 48 (2) ◽

pp. 426-427

Author(s):

N. Merk ◽

A. P. Tomsia ◽

G. Thomas

Keyword(s):

Cross Section ◽

Dissimilar Materials ◽

Ceramic Materials ◽

Electron Micrograph ◽

Scanning Electron Micrograph ◽

Structural Applications ◽

Metal Ceramic ◽

The Subject ◽

Ceramic Compounds ◽

Scanning Electron

A recent development of new ceramic materials for structural applications involves the joining of ceramic compounds to metals. Due to the wetting problem, an interlayer material (brazing alloy) is generally used to achieve the bonding. The nature of the interfaces between such dissimilar materials is the subject of intensive studies and is of utmost importance to obtain a controlled microstructure at the discontinuities to satisfy the demanding properties for engineering applications . The brazing alloy is generally ductile and hence, does not readily fracture. It must also wett the ceramic with similar thermal expansion coefficient to avoid large stresses at joints. In the present work we study mullite-molybdenum composites using a brazing alloy for the weldment.A scanning electron micrograph from the cross section of the joining sequence studied here is presented in Fig. 1.

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