It is well established that SMAs have a great important as: engineering and biomaterial applications, because of unique properties that had as well as, good biocompatibility. however, duo to its possible corrosion in physiological solution, dissolution of toxic Ni might be happening. Several studies have been carried out to improve the stability of the passive protective film of Tio2 and prevent the Ni ion relies out of NiTi. Surface treatment is one of these methods or techniques such as, ion implantation, plasma electro polishing, passivation, ultra-sonic treatment and laser treatment, most of these treatments are effects on transition temperatures (As,Af,Ms,Mf). Change of these temps. will affected the normal use especially in human body, so keeping these temps. within the range of the human body is of main requirements to Evaluation the efficiency of any treatment. In this study (55 wt% Ni, 45 wt % Ti) SMAs has been prepared by (PM), compacted at 850 MPa and sintered. Laser pulses deposition technique at (1064, 532) nm at different energy (2, 2.3, 2.7) J. At power (200) wat in constant duration time (2 ns) has been used to modify surface by continuous stricks (side by side) to study mechanical, corrosion properties and how laser pulses effects on transition temp. All results confirmed that there is a positive effect on properties, % improving in hardness with respect to reference sample are (145, 132.8, 123.8) and (180.9, 169.5, 152.3) at 1064, 532 wave length respectively. Improvement in Ni relies are equal to (52, 38) % with respect to reference sample. On the other hand, there are slight positive change on transition martensitic transformation, thermal hysteries ( As−Ms) there are reduction in degress from 50°C (untreated sample) to (36.9, 33.6)°C, while for martensitic transformation ( Af−Mf) the degress are decrease from (65)°C for untreated sample to (57.5, 51.7)°C wave length respectively.
This paper included an explanation of one of the methods of protection from corrosion, as it dealt with the use of electroplating technology by using solid ceramic particles embedded in chromium on carbon steel as a base material as an effective way to increase the service life of fluid-carrying tubes, considering that they are exposed to a joint effect of chemical and physical action. The formation of composite coatings on carbon steel and the factors affecting the success of these coatings in addition to a group of studies that dealt with these factors and their impact on increasing the resistance to conditions surrounding the metal represented by resistance to chemical corrosion in the presence of erosion (such as the concentration of solid particles in the paint solution, the temperature of the paint solution, the effect of The current density on the quality of the coatings and the effect of the thermal treatment on the coatings). The current density, the concentration of solid particles and the temperature have the greatest influence in determining the efficiency of the composite coatings.
Heat treatments are the most common method of transforming or modifying the structure of white cast iron. Cementite tapes can be decomposed at high temperatures and over a long period of time. These thermal treatments require special furnaces and a long period of time, as well as a high cost with major problems associated with these techniques. In this study, a mechanical thermal treatment was employed, which includes two basic stages, the first being heating at a certain temperature 1100℃ for a rather short period of time, then applying sequential strokes (one stroke or group of strokes) for a period not exceeding a few minutes. The findings proved that heating for short or long periods of time and at 1100℃ is not sufficient to get rid of cementite tapes, as the structure remained white cast iron. The important matter here is that the effect of the hot impact on the transformation of white cast iron into grey is related to the formation ratio. In this regard, the results uncover that using hot impact and at the same temperature, but at higher rates of forming (i.e., greater than 70%) the structure is completely transformed into grey cast iron.
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