Improvement in Metal-on-Metal Bearing of Hip Implants with Advanced Stellite Alloys
Bibliographic record
Abstract
CoCrMo alloy Stellite 21, which is a low-carbon Stellite alloy, has been used as hip implant material for a number of decades.However, its limited metal-on-metal bearing has resulted in loosening between the femoral head and acetabular cup of hip implants.As a result, there is a strong demand from the hip implant material industry for effective materials with improved metal-on-metal bearing.Three advanced Stellite alloys, highcarbon Stellite 720, Stellite 21 with addition of 10 wt%Cr (named modified Stellite 21) and Stellite 21 with addition of 0.4 ~ 0.6 wt%CrN (named nitrided Stellite 21), are proposed in this research.The wear and corrosion resistances of these alloys are investigated.The wear test is performed on a pin-on-disc tribometer at room temperature.The corrosion tests are conducted in the simulated human body environment (Hank's solution with pH 7.4 at the temperature of 37º C), which include the electrochemical tests of open circuit potential, cyclic polarization, potentiaostatic and electrochemical impedance spectra (EIS), and immersion test.The experimental results demonstrate that the proposed alloys all exhibit better wear resistance than the conventional hip implant material, Stellite 21, either due to increased carbide volume fraction or because of the solid solution strengthening.The corrosion resistance of modified Stellite 21 is much better than that of Stellite 21.Although Stellite 720 and nitrided Stellite 21 are worse than Stellite 21 in corrosion resistance, they are still very corrosion resistant to Hank's solution.Therefore, all the three alloys are recommended for potential hip implant materials, but modified Stellite 21 with combined superior wear and corrosion resistance properties is highly recommended.3.2.1 Test facilities.......
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".