YY/T 1074-2002Implants for surgery--Measuring method for pitting corrosion potential on stainless products (English PDF)

Foreword

This standard adopts the test solution and test temperature provisions of the simulated human physiological environment that are specified in No. 405, 406 "New Working Item" proposed by the International Organization for Standardization (ISO) Technical Committee 150 on October 24, 1997.For the test instruments and equipment, sample preparation, and test steps, reference is made to some provisions in GB/T 17899-1999 "Method of Pitting Potential Measurement for Stainless Steels". Appendix A and B of this standard are normative.

YY 91074-1999 (ZB C35 005-1985) "Corrosion Test Methods for Metallic Bone Plates and Bone Screws" shall be abolished, since the issuing date of this standard.

This standard was proposed and approved by China Food and Drug Administration.

1 Scope

This standard specifies the definitions of measuring method for pitting corrosion potential on stainless surgical products; and the requirements of the measuring system's test instruments and equipment, sample preparation, test conditions and steps, test result, and test report.

This standard is applicable to the measurement that adopts potentiodynamic method to measure the pitting corrosion potential of stainless surgical implant products in the simulated human physiological environment.

2 Normative References

The articles contained in the following documents have become part of this standard when they are quoted herein. For the dated documents so quoted, all the modifications (excluding corrections) or revisions made thereafter shall not be applicable to this standard. For the undated documents so quoted, the latest editions shall be applicable to this standard.

GB/T 1266-1986 Chemical reagents - Sodium chloride

3 Terms

For the purpose of this standard, the following terms and definitions shall apply.

5 Preparation of sample

5.3 Selection of test surface. For plate products, select rolling surface. For rod or wire products, select drawing surface. The test surface shall be away from edge, sharp corner, hole, groove, thread, mark, and welding spot. If there is no flat surface, select smooth spherical surface or cylinder surface.

5.4 Coating of sample. The surface of sample shall be wiped and cleaned by alcohol and acetone. After drying process, use insulating sealant (704 silicone rubber, epoxy resin and vinyl resin) to coat or inset the sample, so as to make the final exposed test surface to be about 1 cm2.If the sample is too small, the test surface can be less than 1 cm2.No crevice or pit is allowed on the insulated coating surface.

6 Test conditions and steps

Appendix A (Normative)

Supplementary explanation A.1 This standard is also applicable to the measurement by adopting manual step-method.

The potential variation speed is to keep constant potential for 1 min per 20 mV, or for 2 min per 40mV. List out the potential and current values; draw the E-logi anode polarization curve.

A.2 When the pitting corrosion potential cannot be determined, check whether the sample has crevice corrosion or coating is properly sealed. If there is crevice corrosion, the corrosion potential value at this point shall be omitted and void; and test shall be re-conducted.

A.3 The pitting corrosion potential measured by this standard only indicates the anti-corrosion level of the surface of the product, and represent the quality of the product and the processing level of surface treatment; it does not replace the random defect test of the product surface.