Satit Karoonboonyanan creator Salokhe, Vilas M. Chairperson Panadda Niranatlumpong Chairperson Jayasuriya, H.P.W. Examination Committee Canillas, Emmanuel C. Examination committee Royal Thai Government Fellowship and Thailand Graduate Institute of Science and Technology (TGIST), NSTDA Scholarship donor text series technical report th Pathum Thani, Thailand Asian Institute of Technology 2005 continuing eng 77 leaves : ill. Rotary tiller is an agricultural implement, popularly used for saving labour and time in soil preparation. It can also be used to incorporate residue in sugarcane field into the soil to increase the organic matter content. Despite several usage, wear of rotary tiller blades is quite high, especially in sandy soil, which affect its working life. The main objective of this study was to test the effect of coatings and coating techniques on wear characteristics of rotary tiller blades. This study compared five different thermal spray systems, namely, Arc-sprayed Tungsten Carbide/Nickel (WA), Flame-sprayed "tungsten Carbide/Cobalt (WF), High-velocity oxygen-fuel- (HVOF) sprayed Tungsten Carbide: Cobalt (WH), Plasma-sprayed Alumina/Titania and Plasma-sprayed Alumina/Titania with Nickel Aluminium bond coating (APB), on rotary tiller blades. Four-hectare field tests and 40-hour laboratory tests were conducted to evaluate wear characteristics of the coated blades. Average wear rates of the uncoated blades were 6.58 -,/ha in the field and 0.23 g/h in the laboratory. Wear resistance index (WRI), defined as wear rate of the uncoated blade divided by the coated one, were 0.96, 0.60, 9.90, 1.40 and 1.74 in the field and were 0.98, 0.61. 1.28, 1.13 and 1.12 in the laboratory for N VA. WF, WI I, AP and APB blades respectively. WH was the most resistant both in the laboratory and in the field, while WF was the least. AP and APB showed significant resistance in the field but not in the laboratory. WA did not show significant resistance in both tests. Correlation analysis showed that wear resistance of the coated blades in the field could be predicted by the laboratory test, except for WH as its field performance was much higher than the predicted value. Average costs of rotary tiller blades were 10. 46, 642, 19, 3 1, 48 Baht per hectare for the uncoated, WA, WF, WH, AP and APB blades respectively. It was concluded that application of thermal spray for rotary tiller blades was not economical even though one of them. WH, showed very high performance A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development Thesis (M.Eng.) - Asian Institute of Technology, 2005 Rotary tillers Agricultural implements Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B09247 http://203.159.5.9/ait-thesis/detail.php?q=B09247 060709 20260819090621.0