Page 8 - Докторська дисертація_Ткачук

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blue, aquamarine, which has the prospect of use for implants and medical instruments,

parts of which are given colour to simplify the selection of required shape and size.

It was determined that when modifying non-stoichiometric titanium nitride

with oxygen, nitrogen atoms are replaced by oxygen atoms with the formation of

titanium oxynitride TiNxO1-x on the surface, in which the nitrogen content is

decreased, up to the formation of titanium oxide TiO2. It was determined that by

increasing the oxygen content in titanium oxynitride and the appearance of the TiO2

oxide phase, the corrosion resistance of the BT6 titanium alloy in a physiological

environment is improved due to an increase of the proportion of the ionic bonding in

the coating compounds. It was established that an increase of the oxygen content in

the oxynitride leads to an increase of the cytocompatibility of the BT6 titanium alloy,

and the oxynitride layers of composition TiN0.42O0.58 and TiN0.36O0.64 can be

recommended for further testing of their biological action in vivo.

The optimal composition of the electrolyte of (1М КОН + hydroxyapatite) for

the formation of HA coating on the titanium alloys for medical applications by the

PEO method was determined, which allows to form a porous HA coating with a

spheroidal structure and an optimal Ca/P ratio at a voltage of 160 V in a pulsed regime.

The regularities of formation of HA coatings on preformed nitride layers of

Ti2N and TiNx were established. It was shown that the corrosion resistance of the

Ti2N+HA coating in Ringer's solution is higher compared to TiNx+HA. It was

established that the value of Young's modulus for the HA coating deposited on the

Ti2N nitride layer is close to the corresponding value for a cortical bone.

It was established that with the transition from titanium nitride to oxynitride by

increasing oxygen content in the oxynitride, the Ca/P ratio is changed from values >

2 to the ratio characteristic of biological HA, which leads to an improvement of the

corrosion resistance of HA coating. The mechanisms of formation of HA coatings on

pre-modified surfaces of the titanium alloys for medical applications were established.

Scientific novelty of the obtained results.

1. For the first time, the general regularities of the influence of the phase-structural

state of modified layers formed on titanium alloys for medical applications by