Carbon-containing material with double carbides for implants

FIELD: prosthesis techniques.

SUBSTANCE: invention, in particular, relates to cardiovascular surgery involving use of artificial mitral valves and also can be utilized in manufacture of implants of other organs in orthopedics, stomatology, traumatic surgery, and the like, as well as in various technical fields. Material of invention contains boron, silicon, and isotropic pyrocarbon in specified proportions.

EFFECT: increased strength, hardness, and wear resistance.

1 tbl, 3 ex

 

The present invention relates to medicine, in particular for cardiovascular surgery and related prosthetics artificial heart valves (ICS), and can be used in the manufacture of implants other bodies in orthopedics, dentistry, traumatology and others, as well as in various areas of technology.

Known carbon-containing material LTI (Low Temperature Isotropic form Pyrolitic Carbon)containing 10 wt.% silicon (Si) [1]. Isotropic pyrocarbon LTI obtained by gas-phase pyrolysis of hydrocarbons in plants with fluidized bed. LTI is used only in the form of a coating thickness of 250 microns on a graphite substrate specific configuration for the manufacture of elements of X. The technology provides for individual processing of each part. Physico-mechanical properties of LTI are shown in table 1. Practical application of the method based on fluidized bed technology is limited due to the impossibility of obtaining pyrolytic deposition with a thickness sufficient for the manufacture of monolithic products.

Known carbon-containing material placecall [2], containing 12-18 wt.% boron (B). This material is chosen as a prototype, produced by pyrolysis in the form of monolithic deposition with a thickness sufficient to produce the parts of X. Physico-mechanical properties of placitella given in ablaze 1. However, the strength and hardness of placitella lower than the LTI.

The aim of the invention is to increase the strength, hardness and wear resistance of placitella.

This goal is achieved by the fact that the proposed material

includes, wt.%:

Bor1-19
Silicon1-9
Bor + siliconNo more than 20
Isotropic pyrocarbonThe rest of it.

The difference of the material is above the ratio of components.

The proposed composition of the material is selected on the basis of the physico-mechanical characteristics of complex biomedical research and testing samples of the material.

Physical-mechanical properties and test results on the toxicology and thromboresistant all materials containing boron in the range of 10-20 wt.% or silicon 10 wt.% and isotropic pyrocarbon - rest, satisfy the requirements of material for implants. However, pleasetell has the strength, hardness, and therefore, the wear resistance is lower than the LTI. In turn, the technology for LTI does not allow pyrocarbon deposition with a thickness sufficient for the manufacture of elements of X.

The basis pre the proposed of the invention is to increase strength, the hardness and durability of placitella by introducing into the composition of silicon to 9 wt.%. This will allow you to get pyrocarbon deposition with a thickness sufficient for the manufacture of elements of X, and higher physical and mechanical properties.

The method of obtaining material of the proposed structure is based on a three-dimensional crystallization of carbon from the gas phase with subsequent condensation on the surface of the substrate. Carry out the process in vacuum pyrolysis reactor. For reactor f mm as the substrate used, the inner surface of the cylinder of graphite. Reagents: natural gas, propane, boron trichloride (BCl3), methyltrichlorosilane (CH3Cl3Si), or trichlorosilane (SiHCl3), or silicon chloride (SiCl4) and inert gas (e.g. nitrogen). The composition of the material governs the ratio of the injected reagents.

Example 1.

Material composition: Bor 9 wt.%, silicon of 1 wt.% and isotropic pyrocarbon 90 wt.%. The material of such a composition has the following physical and mechanical properties:

Density, g/cm31,80-2,10
Bending strength, MPa300-400
Microhardness kg/mm2100-150
The crystallite size, nm8-9

Example 2.

Stood the material: boron 10 wt.%, silica 5 wt.% and isotropic pyrocarbon 85 wt.%. The material of such a composition has the following physical and mechanical properties:

Density, g/cm31,80-2,10
Bending strength, MPa350-450
Microhardness kg/mm2120-170
The crystallite size, nm7-8

Example 3.

Material composition: Bor 11 wt.%, silicon 9 wt.% and isotropic pyrocarbon 80 wt.%. The material of such a composition has the following physical and mechanical properties:

Density, g/cm31,80-2,10
Bending strength, MPa400-500
Microhardness kg/mm140-200
The crystallite size, nm6-7

Table 1 shows the physico-mechanical properties of isotropic pyrocarbon material. From an analysis of the table shows that the proposed material has occupied an empty place among these materials. Physico-mechanical properties gradually change from pyrographite isotropic without alloying elements to the material LTI-doped silicon.

Thus, the material of the proposed structure has a higher strength and hardness than uglesich the L. This will increase the wear resistance of elements of X and, consequently, will increase the durability and reliability of ICS. The material we will make it durable and reliable dental implants, implants of various joints and other medical products.

Table 1

Physico-mechanical properties of isotropic peroperative
PropertiesPyrographic isotropic (PIP)PlacecallThe material proposed compositionLTI
Density, kg/m3Of 1,800-2,100Of 1,800-2,100Of 1,800-2,1001700-2200
Alloying elementnoInB+SiSi
The crystallite size, nm16-209-106-93-5
Microhardness kg/mm40-7070 -140100-200230-370
The modulus of elasticity, GPA13-1520-2523-2827-31
Flexural strength, MPa100-150250-450300-500350-530

References

1. Duskardt R.H., Ritche R.O., Pyrolitic carbon coatincs,// In: L.L. Hench, Wilson.

J. (eds). Singapore, World Scientific Publ. Co. - 1993: 261-279.

2. Patent RU No. 2163105 C1, A 61 F 2/24, 20.02.2001.

Carbonaceous material for implants containing isotropic pyrocarbon and boron, characterized in that it additionally contains silicon in the following ratio, wt.%:

Bor1-19
Silicon1-9
Isotropic pyrocarbonRest

provided that

Bor + siliconNo more than 20



 

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