Tribo-Thermal Based Evaluation of Non Asbestos Disc Brake Pad Formulation

Performance of Non Asbestos brake pad requires the optimization of numerous criteria. Alumina fibre is a metallic material which is light weight, excellent wear resistance, thermal stability and structural reinforcement properties. Hence the present work deals with the development of three friction composites in the form of standard disc brake pads using same ingredients in same proportion except alumina fiber containing 7%wt, 11%wt & 14% wt which is compensated by synthetic barites (filler) containing 16%wt, 12%wt & 9% wt and designated as NA01, NA02 and NA03 respectively. Various physical, thermal and mechanical characterizations are carried out as per IS2742 Part 3 standards in which the loss of ignition decreased while the specific gravity, compressive strength and hardness increased with the fiber increase. Then the tribological properties (Fade and Recovery) are tested using Chase Test following IS2742 Part 4 standards. The fade μ and recovery μ % were significantly influenced by the amount of fibre combinations. It was proved that, increase in amount of alumina fibre % had significant effect on fade μ %.Thermo Gravimetric Analysis (TGA) proves that higher fiber content has more thermal stability leading to good fade resistance. Over all NA03 formulation is proved as superlative performer.

Hydroxyapatite Matrix Composites by Hot Isostatic Pressing: Part 1. Alumina Fibre Reinforced

Fracture Toughness Improvement of the Hydroxyapatite Matrix Composite, to a Level Comparable to that of Natural Bone for in Vivo Applications, Was the Aim of the Present Work. Hot Isostatic Press Using a Graphite/stainless Steel Encapsulation System Enabled the Production of Fully Dense Decomposition-Free Hap with Toughness Improvements of: 2.4 Times (Al2O3 Fibres, Optimally 20 Vol%). Glass Encapsulation of Fibre-Reinforced Hap Resulted in Aeration from Sample Volatilization. Further, it Was Found that the Hap Decomposition Temperature Was Higher at 100 Mpa (the Hiping Pressure) than for Pressureless Sintering. the Toughening Effect of the Al2o3 Fibre Additive Induced Plastic Deformation and Ductile Fracture.

Effect of the Infiltration Pressure on the Properties of Composite Wires

Nowadays the development of composite materials has increasing importance. In this study Nextel 440 type alumina fibre reinforced aluminium matrix composite wires were investi-gated. Composite wires produced using the continuous process are suitable to simplify the introduc-tion of fibre reinforcements into aluminium castings as well as the production of double composite, sandwich and preferentially reinforced structures. This paper focuses on the porosity of composite wires because minimizing porosity is the primary condition of good mechanical properties. Compo-site wires were produced with different infiltration pressures (0.83 MPa, 1.03 MPa, 1.24 MPa, 1.52 MPa, 1.65 MPa 1.86 MPa and 2.07 MPa) and different diameters (1 mm and 2 mm) to determine the correlation between infiltration pressure and the porosity of wires. 10 grinded cross-sectional samples were made from each type of composite wires. Based on the micrographs of these samples the volume fraction of aluminium was determined by image analysis, which also yielded informa-tion on the porosity of wires. The results show that there is direct linear correlation between the infiltration pressure and the change in porosity. These findings, however, are valid only for the in-vestigated range of pressure.