NOPR Collection:

Effect of ultrasonic agitation on surface finish of electrodeposits

1994-06-01T00:00:00Z

Title: Effect of ultrasonic agitation on surface finish of electrodeposits Authors: Prasad, P B S N V; Vasudevan, R; Seshadri, S K Abstract: Use of ultrasonics during electrodeposition has been carried out to obtain the smoother deposits and to improve its hardness. A comparison has been made between the deposits obtained from a still bath and an ultrasonically agitated bath. The surface finish of the deposited samples has been studied using a perthometer. Page(s): 178-180

Tribological studies of some N and S heterocyclic compounds in lithium grease

1994-06-01T00:00:00Z

Title: Tribological studies of some N and S heterocyclic compounds in lithium grease Authors: Singh, T; Bhan, A K; Chandrasekharan, C V Abstract: Some 5-arylamino-2-mercapto-1,3,4-thiadiazole additives, blended with lithium grease (0.5, 1.0, 1.5 & 2.0% w/w) have been evaluated as extreme pressure additives in a four-ball test. The additives lower friction as well as wear and function well even at high temperature and pressure as compared to commercially available lithium base EP grease. The blended greases were found to pass corrosion, oxidation stability as well as roll stability tests. The 2% w/w admixture of 5-p-methoxyphenylamino- 2-mercapto-1,3,4-thiadiazole with lithium grease exhibited a weld load of 360 kgf,whereas, the reference lithium base EP grease and lithium grease without additive afforded the weld load values of 260 and 160 kgf, respectively. The topography and tribochemistry of the used balls after four-ball test were studied using scanning electron microscopy and EDAX techniques, respectively. The EDAX analysis showed the presence of sulphur in the wear tracks and it was found to enhance the EP activity of the additives. Page(s): 173-177

The behaviour of different cement pastes in various sulphate solutions

1994-06-01T00:00:00Z

Title: The behaviour of different cement pastes in various sulphate solutions Authors: Ali, A H; Amin, A M; Sharara, A M; EI-Didamony, H Abstract: Ordinary portland, sulphate resisting and pozzolanic cement (made from 80% portland cement and fired clay) pastes were immersed in 5% solution of (NH₄)₂SO₄, MgSO₄ and Na₂SO₄ up to one year. The sulphate attack was followed by determining the compressive strength of the hardened pastes, the amount of penetrated sulphate and free lime. The penetrated sulphate content and its relation with lime as well as the resulting pH and hydration products have a deleterious effect on the stability of CSH and hence the strength of the hardened pastes. (NH₄)₂SO₄ has the highest aggressive action on cement pastes whereas pozzolanic cement pastes show the highest resistivity to sulphate attack. Page(s): 169-172

Macromechanism for slurry abrasion of short fibre reinforced polyester composite

1994-06-01T00:00:00Z

Title: Macromechanism for slurry abrasion of short fibre reinforced polyester composite Authors: Chand, Navin; Fahim, M Abstract: A theoretical model to estimate the wear loss behaviour and erosive mechanism of polymer composites has been developed, Fibre reinforced polyester composites subjected to sea water erosive environment through a slurry of hard, angular sand particles, NaCl and water have been tested in a slurry pot erosion tester for different time intervals, Eroded surfaces of the composites have been examined on a scanning electron microscope. A comparison of experimental and calculated values for erosive wear loss of fibre reinforced polyester composites has also been made. Page(s): 165-168