Thermal cycling behavior of nanostructured and conventional yttria-stabilized zirconia thermal barrier coatings via air plasma spray

Two thermal barrier coating(TBC)systems comprising NiCoCrAlY bond coat onto a second-generation Ni-based single crystal superalloy and nano structured4 mol%Y_(2)O_(3)-stabilized ZrO_(2)(4YSZ)and conventional yttria-stabilized zirconia(YSZ)top coats upwardly were deposited by approaches of arc ion plating(AIP)and air plasma spray(APS).As indicted by the experimental results,the 4YSZ TBCs exhibited superior thermal cycling resistance compared with conventional YSZ TBCs at 1100℃.The 4YSZ top coat exhibited higher toughness due to its intrinsic property of nanocrystalline structure,homogeneously distributed and diverse directions of pores and preexisted cracks.The cracks and spallation in 4YSZ TBCs occurred at the interface of top coat and thermally grown oxide(TGO)layer.Instead,the crack initiation and propagation started along the lamellar interface in the top coat of conventional YSZ TBCs,leading to the rapid crack bridging and subsequent spalling of top coat.Additionally,before and after oxidation,the 4YSZ top coat showed higher hardness compared to conventional YSZ top coat.Degradation mechanism and distribution of residual stress in TGO for the 4YSZ TBCs were investigated in the current study.

Clinical observation on 30 cases of external humeral epicondylitis treated with electroacupuncture at Zhouling and Ashi points combined with blood-letting cupping

Objective:To observe the clinical effect of electroacupuncture(EA)at Zhouling(Extra)and Ashi points in combination with blood-letting cupping for the treatment of external humeral epicondylitis(EHE).Methods:Thirty EHE patients were treated with EA at Zhouling(Extra)and Ashi points in combination with blood-letting cupping,once every 2 days,twice a week,4 times as one course of treatment,and2 successive courses of treatment were given.Before treatment,after 1 course of treatment,and after 2 courses of treatment,the visual analogue scale(VAS)score and Mayo elbow performance score(MEPS)were adopted to evaluate the curative effect.Results:Before treatment,the VAS score of patients was 7.81±1.39.After 1 course of treatment and after 2 courses of treatment,it was 4.77±1.56 and 2.95±1.23 respectively,lowered than before treatment,and the difference was statistically significant(both P<0.01).Before treatment,the Mayo score of patients was 32.17±19.31.After 1 course of treatment and after 2 courses of treatment,it was 47.39±19.85 and85.21±20.47 respectively,increased than before treatment,and the difference was statistically significant(both P<0.01).Of the 30 patients,5 were cured,accounting for 16.67%;14 cases obviously effective,accounting for 46.67%;8 cases effective,accounting for 26.67%;3 cases ineffective,accounting for 10.00%,and the total effective rate was 90.00%.Conclusion:EA at Zhouling(Extra)and Ashi points and blood-letting cupping used in combination are remarkably effective in the treatment of EHE,being worthy for popularization.

Oxidation Performance and Interdiffusion Behavior of a Pt-Modified Aluminide Coating with Pre-deposition of Ni

To refrain the interdiffusion of elements while holding good oxidation resistance,a(Ni,Pt)Al/Ni composite coating was prepared by sequential treatments of electroplating Ni and Pt and successive gaseous aluminization.In comparison with normal(Ni,Pt)Al coating,high-temperature performance of the composite coating was evaluated in isothermal oxidation test at 1100℃.Both the two coatings exhibited good resistance against high-temperature oxidation,but the interdiffusion of elements between composite coating and single-crystal(SC)superalloy substrate was greatly relieved,in which the thickness of secondary reaction zone(SRZ)and the amount of precipitated topologically close-packed phase in the SC alloy matrix were significantly decreased.Mechanisms responsible for delaying rate of coating degradation and SRZ growth/propagation are discussed.

Twenty-eight cases of facial acne treated by quick puncture with collateral-pricking cupping

Objective:To observe the clinical effect of quick puncture with collateral-pricking cupping for facial acne.Methods:Twenty-eight patients with acne were treated with pricking acne spot and abdominal region of three toes for bloodletting combined with collateral-pricking cupping on the back,once every 5 days,for3 weeks in succession.A 3-month follow-up was applied to observe the reducing rate and clinical effect of facial skin lesions after treatment.Results:Of the 28 cases,9 were cured,12 remarkably effective,5 effective,and 2 ineffective.The total effective rate was 92.86%.Conclusion:The effect of pricking acne spot and abdominal region of three toes combined with collateralpricking cupping on the back is good,being worthy of further clinical discussion to promote its application.