Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Entire DC Network
Thermal Stability Of Electrodeposited Liga Ni-W Alloys For High Temperature Mems Applications
Thermal Stability Of Electrodeposited Liga Ni-W Alloys For High Temperature Mems Applications
A.S. Md Abdul Haseeb
For thermally stable LIGA materials for high temperature MEMS applications LIGA Ni-W layers and micro testing samples with different compositions (15 and 5 at% W) were electrodeposited. In order to investigate the thermal stability the Ni-W layers were annealed at different temperatures (300-700°C) and for different durations (1, 4, 16 h). Their microstructure and micro-hardness were than analysed after annealing and compared with those of as-deposited states. The observed microstructures show, in comparison to pure LIGA nickel, a small grain growth and a relatively stable structure up to 700°C. The micro-hardness values of the LIGA Ni-W layers are higher than …
Chemical And Structural Nature Of Tribo-Surface Of Aluminium-Sic Composites At Nanometre And Micrometre Length Scales
A.S. Md Abdul Haseeb
The worn surface of Al-SiC metal matrix composites (MMC) sliding against phenolic brake pad at a linear sliding speed of 1.62 m s-1 under contact pressures of 0.75-3.00 MPa in a pin-on-disc apparatus was investigated. XPS was used to extract information from the top few nanometres of the worn surface, while scanning electron microscopy and energy dispersive X-ray microanalysis (SEM-EDX) provided information from within a few micrometres. Results reveal that the surface of Al-SiC undergoes significant chemical and physical changes during wear. The tribo-surface on Al-SiC is converted into a mixture that contains the constituents of Al-SiC and the phenolic …
Failure Analysis Of Superheater Tube Supports Of The Primary Reformer In A Fertilizer Factory
Failure Analysis Of Superheater Tube Supports Of The Primary Reformer In A Fertilizer Factory
A.S. Md Abdul Haseeb
A failure analysis of superheater tube supports of the primary reformer in a local fertilizer factor is presented. A number of tube supports failed at approximately half of their designed service life. Following the failure, the factory was visited, and relevant information and samples were collected. The samples were investigated in the laboratory by chemical analysis, macro- and microhardness measurements, macro-and micrometallographic examinations, and X-ray diffractometry. The analysis showed the supports were fabricated from HH-type heat-resisting alloy and that the failure mode was high-temperature creep. The microstructure of the alloy showed the presence of massive intergranular as well as intragranular …