Hydroxyapatite coating of TiNi shape memory alloy via Electrophoretic Deposition (EPD)

ABSTRACT

In this study, hydroxyl apatite (HA) as a bio-ceramic is coated on the TiNi shape memory. In this approach, Tri-ethanolamine and butanol were used as suspensions. To set up Electrophoretic Deposition (EPD) process, voltages of 20, 30 and 40 volts were applied on the cathode for 1-5 minutes. The sintering process was done in the Ar atmosphere for two hours at 800°C. SEM and XRD were used to investigate surface morphologies and phases. Obtained results showed that higher electrical currents led to generation of thicker coatings registering 105% and 12.3% improvement for weight and thickness after 6 minutes, respectively. Moreover, Transformation of HA to other calcium phosphate phases doesn’t happen at a sintering temperature of 800°C. Moreover, a uniform, homogeneous and crackles coating can be reached in the voltage of 30 volts at low sintering temperatures. This process can be utilized an alternative technique for bioactive coatings.

KEYWORDS:

• TiNi shape memory alloy
• hydroxyapatite
• coating
• Electrophoretic Deposition

Disclosure statement

No potential conflict of interest was reported by the author(s).

Statement of novelty

Our results show that the proposed approach in this study led to coating of TiNi shape memory alloy by HA coating layer. Obtained results showed that higher current led to generation of a thicker coating. Moreover, transformation of HA to other calcium phosphate phases does not happen at a sintering temperature of 800°C. Moreover, a uniform, homogeneous and crackles coating can be reached in the voltage of 30 V and at low sintering temperatures. Also, both of thickness and weight of layers increased at higher deposition times. In comparison with other deposition techniques such as plasma and sol-gel coating, this process can be utilised as an alternative for bioactive coatings.