Search results

The purpose of this paper is to investigate the effect of SiC addition up to 60 percent SiC on the mechanical properties and thermal expansion of Al‐7vol.% Si/SiC composites.

Composite specimens containing 7, 15, 30, 45 and 60 vol.% SiC_p are fabricated by pressureless infiltration technique. The obtained metal‐matrix composites (MMCs) then are characterized for density, porosity, microhardness, ductility, and coefficients of thermal expansion (CTE).

The results show that the composite specimens have very low‐porosity volumes. Moreover, it is found that silicon carbide particles are distributed uniformly in the matrix. Both porosity and mean linear CTE of the composites decreases with silicon carbide volume fraction. However, higher amount of SiC_p reinforcement content tends to increase density, microhardness and improve ductility.

The processing employed in this paper would enable realization of electronic packages made out of Al‐Si/SiC_p MMCs.

It is aiming at finding tribology performance laws and mechanism of sintering materials, including new materials, which are popular or potential materials of mechanical seals working under water condition with different working parameters, involving load and sliding speed.

Falex-1506 tribo-machine has been used. The upper sample is rotated against the stationary sample below. They are all rings. The samples are WNV2, sintered pressureless bonded; CHV1, graphite-added PLSiC; R, sintered reaction bonded; R2, graphite-added RBSiC, cemented carbide YN6 and graphite MSMG. Twenty kinds of hard/hard and soft/hard pairs were tested under water condition. Then, SEM was used to observe the sliding surface to explain their rubbing mechanism.

Friction coefficients decrease with the load increasing under water lubrication due to water holding by small holes on their surface. But the friction coefficients have no change with the varying of velocity. The hard alloy/sintered silicon carbon pairs may be better choice, where the lowest friction coefficient is only about 0.02, than soft/hard or silicon carbon/silicon carbon pairs under water lubrication, especially under heavy load.

The test was carried under load from 89 N (0.7 MPa) to 356 N (2.80 MPa) and sliding velocity from 0.746 to 5.074 m/s where the lubrication is in mixed.

The detailed values of frictional coefficients of popular and potential sintered material of mechanical seals working under water lubrication were given by the experimental research which may be helpful for the choice of mechanical seal materials.

Submarine propeller shaft seals operate under onerous conditions in an aggressive environment and their effective life is vitally dependent upon the durability of the seal face materials. The combination of physical and mechanical properties of certain carbon‐carbon composites makes them potentially suitable for this critical service, but a literature search revealed no prior reference to their deployment in any liquid sealing application nor, indeed, to their behaviour in an aqueous environment. In consequence, a programme of work has been carried out to determine the effect of prolonged exposure to high‐pressure sea water upon their properties, and to assess their performance when run in a seal test rig against a variety of counter surfaces. The assessments were made under a reproducible condition of boundary lubrication stabilised by control of interface torque. The effects of composite anisotrophy and of graphitisation have been examined using specimen rings with the direction of fibre lay‐up either in, or normal to, the rubbing plane, and in the graphitised or non‐graphitised condition. It has been shown that the carbon‐carbon composites are stable in water and perform well as a seal face material; however, current high procurement cost will probably restrict their use to the more exacting applications.

This paper gives a bibliographical review of the finite element methods (FEMs) applied to the analysis of ceramics and glass materials. The bibliography at the end of the paper contains references to papers, conference proceedings and theses/dissertations on the subject that were published between 1977‐1998. The following topics are included: ceramics – material and mechanical properties in general, ceramic coatings and joining problems, ceramic composites, ferrites, piezoceramics, ceramic tools and machining, material processing simulations, fracture mechanics and damage, applications of ceramic/composites in engineering; glass – material and mechanical properties in general, glass fiber composites, material processing simulations, fracture mechanics and damage, and applications of glasses in engineering.

This study aims to develop and evaluate an inexpensive and durable metal cutting wheel using thermal spraying and polymer binding to enhance the wheel’s cutting capability by bonding hard particles (abrasives) onto the wheel.

Thermal spraying was used to deposit the coating powder (chromium and silicon carbide) onto high carbon substrate. Wear loss and depth of cut as function of load, time and speed were evaluated on uncoated and coated wheel.

The coated cutting wheel performed better than the uncoated cutting wheel in terms of wear performance. However, the coated cutting wheel experienced coating peel off at higher load and cutting speed, leading to a decrease in wear resistance of the cutting wheel. Thus, optimally cutting should be performed either at low cutting speed and high load or at high cutting speed and low load to prolong the wheel’s lifetime.

The outcome of the study will be beneficial for academicians and industrial working on cutting wheel process.

Considers the role of a range of materials being used in advanced sensor technology, including diamond, fullerenes, silicon carbide, superconductors, rare earths and III‐V compounds. Sensors based on these materials are described and their applications discussed.

The purpose of this study is to prepare a state-of-the-art review on advanced ceramic materials including their fabrication techniques, characteristics, applications and wettability.

This review paper presents the various types of advanced ceramic materials according to their compounding elements, fabrication techniques of advanced ceramic powders as well as their consolidation, their characteristics, applications and wetting properties. Hydrophobic/hydrophilic properties of advanced ceramic materials are described in the paper with their state-of-the-art application areas. Optical properties of fine ceramics with their intrinsic characteristics are also presented within. Special focus is given to the brief description of application-based manipulation of wetting properties of advanced ceramics in the paper.

The study of wetting/hydrophobicity/hydrophilicity of ceramic materials is important by which it can be further modified to achieve the required applications. It also makes some sense that the material should be tested for its wetting properties when it is going to be used in some important applications like biomedical and dental. Also, these advanced ceramics are now often used in the fabrication of filters and membranes to purify liquid/water so the study of wetting characteristics of these materials becomes essential. The optical properties of advanced ceramics are equally making them suitable for many state-of-the-art applications. Dental, medical, imaging and electronics are the few sectors that use advanced ceramics for their optical properties.

This review paper includes various advanced ceramic materials according to their compounding elements, different fabrication techniques of powders and their consolidation, their characteristics, various application area and hydrophobic/hydrophilic properties.

This review paper reveals the literature on ultrasonic, chemical-assisted ultrasonic and rotary ultrasonic machining (USM) of glass material. The purpose of this review paper is to understand and describe the working principle, mechanism of material removal, experimental investigation, applications and influence of input parameters on machining characteristics. The literature reveals that the ultrasonic machines have been generally preferred for the glass and brittle work materials. Some other non-traditional machining processes may thermally damage the work surface. Through these USM, neither thermal effects nor residual stresses have been generated on the machined surface.

Various input parameters have the significant role in machine performance characteristics. For the optimization of output response, several input parameters have been critically investigated by the various researcher.

Some advance types of glasses such as polycarbonate bulletproof glass, acrylic heat-resistant glass and glass-clad polycarbonate bulletproof glass still need some further investigation because these materials have vast applications in automobile, aerospace and space industries.

Review paper will be beneficial for industrial application and the various young researcher. Paper reveals the detail literature review on traditional ultrasonic, chemical assisted ultrasonic and rotary USM of glass and glass composite materials.

In this study, powder mixed electro discharge machining (PMEDM) has been performed for the machining of AISI 304 stainless steel by using the tungsten carbide electrode when silicon carbide (SiC) powder is mixed with kerosene. The purpose of this study is to find the optimal value and ascertain the effect of significant machining parameters on surface crack density (SCD) of a machined surface of AISI 304.

A face-centered central composite design-based response surface methodology has been adopted for designing this experiment.

An increase in peak current and powder concentration decreases SCD, which is the main goal of this investigation.

From this investigation, an optimal value has been achieved to minimize the SCD and prevent fatigue and corrosion resistance of the workpiece.

Summarizes briefly the dramatic advances made in the reliability of mechanical seals for rotating shafts in the process chemical and petrochemical industries over the last 30 years. Shows that expected mean time before failure has improved from tens of days to years over that time.