Application of Ball Cratering Method to Study Abrasive Wear

Abstract

The present paper discusses the feasibility of a new use of the ball cratering technique (Calotest) for studying the abrasive wear resistance of hard coatings. The few modifications that were necessary to make the Calotestequipment suitable for this task mainly concerned the calibration of rotational velocity and the controlled delivery of the abrasive–lubricant mixture. Three different types of material were tested to show the capability of the proposed method. These materials were: mono crystalline Si (100) wafers, plain carbon steel, and electroless Ni–P coatings on plain carbon steel in both the as deposited and heat treated conditions. The reproducibility of the values of the wear constants determined by means of the formulationdescribed in the literature prove that the ball cratering test is reliable for the determination of the abrasive wear behaviour of any of thecoatings studied.

Wear mechanisms in ball-cratering tests with large abrasive particles

“…[2,3,5]) and the rigs are commercially available. In some tests a stream or a layer of dry abrasive grits is used [2,7] and in other tests the grits are suspended in liquid forming slurry [3,5,[7][8][9][10][11][12]. Testing with slurries better simulates conditions found in mineral processing industries such as alumina, iron ore or nickel production.…”

“…Since three-body abrasive wear is a serious industrial problem many laboratory test methods have been developed to investigate the abrasion wear resistance of engineering materials. Three-body abrasive wear is most commonly simulated on various rubber wheel-type tribometers [2][3][4], steel wheel tribometers [5,6], pin-on-disc tribometers [7] or by using a ball-cratering test [7][8][9][10][11][12]. Some of these tests are standardised (e.g.…”

“…Two designs are available: a free ball [7][8][9][10] and a fixed ball [11,12]. In the former design, used in this study, the ball rests on a plate and drive shaft and is driven by friction.…”

“…This small size of abrasive grits is deliberately chosen to obtain good quality optical images of wear craters for accurate coating thickness determination [13]. Micro-scale abrasion test has also been used for testing the abrasive wear resistance of bulk materials such as tool steel [11], plain carbon steel [10], and glass [12], again using fine abrasive particles. Recent research has shown that the ball-cratering test is also suitable for characterising the abrasive power of various grits [7,14].…”

Influência da adição de NbC e Al₂O₃+TiO₂ nos desempenhos de revestimentos a base de Ni-Al produzidos por aspersão térmica

“…O carregamento se resume unicamente na força normal exercida pela esfera sobre a amostra. Os abrasivos mais utilizados nos testes são SiC 47,57,58 , alumina e diamante 59 . A figura 6 ilustra o equipamento de micro-abrasão tipo "esfera-livre".…”