Abstract: In this paper,the formation of CaSO₄ deposit on heat transfer surface is investigated both theoretically and experimentally.The test run is performed with various treated surfaces and flow velocities. Microphotograph of deposit layer is made.The results obtained are compared with untreated surface under exactly identical conditions in order to determine the suitability and the characteristics of the various treated surface.It is found that the CaSO₄ deposit on the heat transfer surface can be reduced or even prevented by using surface modification techniques, such as dynamic mixing ion beam implantation and dynamic magnetron sputtering.