Home About us Contact
|
Home About us Contact | ||
|
|
||
Scratch Tests (scratch + test)
Selected AbstractsThe Relationship Between Multiple Scratch Tests and Wear Behavior of Hot-Pressed Silicon Nitride Ceramics with Various Rare-Earth Additive SystemsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2008Hideki Hyuga The wear behavior of Si3N4 ceramics sintered with various rare earth additives was studied for nonlubricated sliding under different conditions, and scratch tests carried out in an attempt to correlate the wear behavior. When multiple scratch testing is used the results can be used to indicate the initial wear behavior under fracture-dominated wear of the materials. The additive system used in the sintering of the Si3N4 ceramics affected the specific wear rate under nonlubricated sliding conditions, and under high load conditions, where fracture is dominant, the specific wear rate was shown to increase in samples sintered with lutetium as a consequence of a strong bonding strength between the grains and grain boundary resulting in a higher degree of brittle fracture. [source] The use of the weber tuning fork test and ,scratch test' in postoperative tympanomastoid surgeryCLINICAL OTOLARYNGOLOGY, Issue 6 2006J.R. Buckland Objective., To compare the use of the Weber tuning fork test and ,Scratch test' in postoperative patients following tympanomastoid surgery. Method., Prospective cohort study with control group. Southampton University Hospitals NHS Trust. Secondary care. 19 patients undergoing routine tympanomastoid surgery for middle ear disease and 18 patients undergoing translabyrinthine surgery for lateral skull base lesions. Main Outcome Measures., Localisation of Weber tuning fork. Positive or negative Scratch test: clinician applies a gentle scratch using index finger to the bandage over the operated ear. Postoperative pure tone audiometry. Results., In the context of diagnosing a hearing or non-hearing ear, the Weber test had a specificity of 78% and sensitivity of 100%. The scratch test had a specificity of 100% and sensitivity of 100%. The Weber was 93% specific and 93% sensitive for diagnosing a unilateral conductive hearing loss. Conclusions., As a means of diagnosing an acute postoperative dead ear the Scratch test is an accurate alternative to the Weber test. References 1 Miltenburg D.M. (1994) The validity of tuning fork tests in diagnosing hearing loss. J Otolaryngol. 23, 254,259 2 Behn A., Laszlo C.A., Black D., et al. (2005) Which is mightier, the tuning fork or the bone oscillator? J Otolarygol. 34, 135,139 [source] A New Analytical Model for Estimation of Scratch-Induced Damage in Brittle SolidsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2007Xiaoning Jing Scratch tests are of fundamental interest both for understanding machining-induced damage and for evaluating the scratch resistance of brittle materials. An improved blister field model for the scratch process is proposed where the blister field strength is explicitly determined in terms of the material properties, loading conditions, and geometry of the scratch tool. Additionally, one new expanding cylindrical cavity model is implemented to estimate the plastic zone size surrounding the scratch groove. A quantitative evaluation of the damage zone size is conducted by combining the above two models. The predicted damage zone sizes are in good agreement with the results available elsewhere in literature. [source] Gold Coating of Poly(ethylene terephthalate) Modified by Argon PlasmaPLASMA PROCESSES AND POLYMERS, Issue 1 2007Vladimír Kotál Abstract Little information has been published concerning the interaction of gold with polymers. In the context of this lack of information, we decided to investigate the effect of Ar plasma treatment on the surface properties of poly(ethylene terephthalate) (PET) in order to examine its possible application for metal-polymer adhesion improvement. The plasma treatment leads to an immediate increase of the PET's surface wettability, which however significantly depends on the sample aging, more specifically on the time elapsed after the treatment. X-ray photoelectron spectroscopy (XPS) measurements revealed that the oxygen concentration in the surface-near layers increases as a result of the treatment, but that it also changes with time for the samples in contact with the atmosphere, probably as a result of polar group rearrangements. Plasma initiated ablation and Au sputtering increases the surface roughness. The nanoindenter measurements revealed that the treatment increases the microhardness of treated PET. Contrary to hardness, the elastic modulus decreases. Scratch tests showed that the deformation of samples consisting of Au coatings deposited on both pristine and treated PET was elastic rather than plastic. We conclude from the nanoindenter data that the plasma modification does not affect the adhesion of gold on PET, but the X-ray diffractometry (XRD) analysis showed that the Au film deposited on the as-treated PET, and on PET aged for 14 d are the most stable. [source] Roles of additives in scratch resistance of high crystallinity polypropylene copolymersPOLYMER ENGINEERING & SCIENCE, Issue 1 2001C. Xiang Scratch behavior in neat and talc-filled high crystallinity polypropylene (PP) copolymers containing various additives is investigated using a cosntant load scratch test and two types of indentation tests (Rockwell and Shore D). The talcfilled PP copolymer exhibits high scratch visibilityand scratch depth. The addition of a nucleating agent or lubricant improves the scratch resistance of the talc-filled PP copolymer. Differential scanning calorimetry, scanning electron microscopy and attenuated total reflectance Fourier transform infrared spectroscopy are used to characterize crystallinity morphology and scratch mechanisms in PP systems. It is found that the scratch resistance of the PP copolymer systems investigated, in terms of scratch depth and scratch visibility, depends mainly on the fracture features generated during the scratch process. The influences of talc, nucleating agent and lubricant on the scratch behavior of PP are discussed. [source] Koebner phenomenon due to scratch test in scleromyxoedemaBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2001B.K. Durani The Koebner phenomenon or isomorphic response was originally described in psoriasis and has subsequently been observed in various other diseases. We report a patient with isomorphic response in scleromyxoedema, a variant of papular mucinosis with diffuse infiltration of the skin. The Koebner phenomenon was due to a scratch test performed 4 weeks before the appearance of streaky, lichenoid infiltrations on the forearms. [source] The use of the weber tuning fork test and ,scratch test' in postoperative tympanomastoid surgeryCLINICAL OTOLARYNGOLOGY, Issue 6 2006J.R. Buckland Objective., To compare the use of the Weber tuning fork test and ,Scratch test' in postoperative patients following tympanomastoid surgery. Method., Prospective cohort study with control group. Southampton University Hospitals NHS Trust. Secondary care. 19 patients undergoing routine tympanomastoid surgery for middle ear disease and 18 patients undergoing translabyrinthine surgery for lateral skull base lesions. Main Outcome Measures., Localisation of Weber tuning fork. Positive or negative Scratch test: clinician applies a gentle scratch using index finger to the bandage over the operated ear. Postoperative pure tone audiometry. Results., In the context of diagnosing a hearing or non-hearing ear, the Weber test had a specificity of 78% and sensitivity of 100%. The scratch test had a specificity of 100% and sensitivity of 100%. The Weber was 93% specific and 93% sensitive for diagnosing a unilateral conductive hearing loss. Conclusions., As a means of diagnosing an acute postoperative dead ear the Scratch test is an accurate alternative to the Weber test. References 1 Miltenburg D.M. (1994) The validity of tuning fork tests in diagnosing hearing loss. J Otolaryngol. 23, 254,259 2 Behn A., Laszlo C.A., Black D., et al. (2005) Which is mightier, the tuning fork or the bone oscillator? J Otolarygol. 34, 135,139 [source] Impact of Grain Size on the Cerchar Abrasiveness TestGEOMECHANICS AND TUNNELLING, Issue 1 2008Klaus Lassnig Mag. The Cerchar abrasiveness test is a common testing procedure for the prediction of tool wear but consistent and detailed recommendations of the testing procedure are inexistent until now. One point of disagreement is the required number of scratch tests per sample to obtain reliable results depending on the grain size of the samples. The focus of this work was to verify the influence of grain size on the number of required single examinations per sample. Grain size analyses were performed to get sum-curves of each tested rock sample. From the grain size data the median and the interquartile range of the grain sizes were calculated. CAI values after 5 and after 10 scratch tests were compared with the median and the interquartile-range of the grain size. No grain size dependency of the CAI deviation between 5 and 10 tests in the analysed range was observed. Einfluss der Korngröße auf den Cerchar Abrasivitätstest Der Cerchar-Abrasivitätstest ist ein häufig verwendeter Indextest zur Ermittlung der Abrasivität von Gesteinen gegenüber Bohrwerkzeugen. Bis jetzt existieren keine einheitlichen und detaillierten Empfehlungen für die Durchführung des Tests. Insbesondere gilt das für die Anzahl der durchzuführenden Tests in Abhängigkeit von der Korngröße der Gesteine. Es existiert lediglich ein Empfehlung, wonach bei grobkörnigen Gesteinen zehn anstatt der sonst üblichen fünf Tests durchzuführen seien. In dieser Arbeit wird der Einfluss der Korngröße auf das Testergebnis in Abhängigkeit von der Anzahl der Tests untersucht. Dazu wurden an den getesteten Proben die Korngrößen bestimmt. Von den Korngrößendaten wurden die statistische Parameter Median und Interquartile-range, berechnet. Die CAI Ergebnisse nach fünf Ritztests und nach zehn Ritztest wurden dann mit dem Median und dem Interquartile-range der Korngrößen verglichen. Im untersuchten Korngrößenbereich wurde kein Einfluss der Korngröße auf die Differenzwerte von fünf und zehn Tests beobachtet. Daraus kann abgeleitet werden, dass im untersuchten Korngrößenbereich die Korngröße , entgegen den bisherigen Annahmen , keinen messbaren Einfluss auf das Ergebnis des CAI-Tests hat. [source] The Relationship Between Multiple Scratch Tests and Wear Behavior of Hot-Pressed Silicon Nitride Ceramics with Various Rare-Earth Additive SystemsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2008Hideki Hyuga The wear behavior of Si3N4 ceramics sintered with various rare earth additives was studied for nonlubricated sliding under different conditions, and scratch tests carried out in an attempt to correlate the wear behavior. When multiple scratch testing is used the results can be used to indicate the initial wear behavior under fracture-dominated wear of the materials. The additive system used in the sintering of the Si3N4 ceramics affected the specific wear rate under nonlubricated sliding conditions, and under high load conditions, where fracture is dominant, the specific wear rate was shown to increase in samples sintered with lutetium as a consequence of a strong bonding strength between the grains and grain boundary resulting in a higher degree of brittle fracture. [source] Abrasive wear mechanisms of VPS- and HVOF-sprayed TiC-Ni based nanocrystalline coatingsMATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 10-11 2004X. Qi Verschleißmechanismen; nanokristalline Schichten; TiC-Ni; thermisches Spritzen Abstract Nanocrystalline coatings have a high potential for various engineering applications, e.g. against wear of rolls in the paper fabrication and as corrosion protection. Using vacuum plasma spray (VPS) and high velocity oxy-fuel (HVOF) spray techniques, coating materials are exposed to high flame temperatures only for less than a millisecond. Therefore, high-energy milled powders can be used as feedstock material without losing its nanocrystalline microstructure during the thermal spray process. In this way, homogeneous, dense nanocrystalline coatings can be produced, which show enhanced hardness, thus obtaining promising superior wear resistance. In the present study, (Ti,Mo)(C,N)-45vol.%NiCo nanocrystalline coatings were prepared by VPS- and HVOF-spraying of high-energy milled powders. Abrasive wear tests JIS H 8615 with varying number of strokes and scratch tests with a Vickers indenter were applied to produce wear traces on the polished surfaces of the nanocrystalline coatings. Abrasive wear behaviour was analyzed by investigating the surface morphologies with optical microscopy (OM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Experimental results indicate that the VPS-coating has higher abrasive wear resistance than the HVOF-coating according to the JIS H8615 test. The abrasive wear mechanism of VPS-sprayed nanocrystalline coatings can be delineated as cutting plus ploughing. For HVOF-sprayed nanocrystalline coatings the abrasive wear mechanism can be described as cutting plus material delamination. Abrasive Verschleißmechanismen von VPS- und HVOF-gespritzten nanokristallinen TiC-Ni-Schichten Nanokristalline Schichten haben ein hohes technisches Anwendungspotenzial, z.,B. für Papierwalzen zum Schutz gegen Verschleiß und Korrosion. Während des thermischen Spritzens mit der Vakuumplasmaspritz (VPS)- und der hochgeschwindigkeits-Flammspritz (HVOF)-Technik werden die Beschichtungsmaterialien nur für weniger als eine Millisekunde den hohen Temperaturen ausgesetzt. Daher können hochenenergiegemahlene Pulver als Beschichtungswerkstoff genutzt werden, ohne dass diese während des Spritzprozesses ihre nanokristalline Mikrostruktur verlieren. Dadurch können homogene, dichte nanokristalline Schichten produziert werden, die hohe Härte aufweisen und damit auch eine hohe Verschleißfestigkeit zeigen sollten. In der vorliegenden Arbeit werden nanokristalline Schichten auf der Basis von (Ti, Mo)(C, N)-45Vol.%NiCo durch die VPS- und HVOF-Technik hergestellt. Verschleißtests nach JIS H 8615 mit unterschiedlicher Hubzahl und Ritztests mit dem Vickers-Indenter werden durchgeführt, um Verschleißspuren auf den polierten Oberflächen der nanokristallinen Schichten zu erzeugen. Die Verschleißmechanismen werden aufgrund der Oberflächenmorphologien von verschleißbeanspruchten Schichten durch optische Mikroskopie (OM), Raster-Elektronenmikroskopie (REM) und Rasterkraftmikroskopie (AFM) analysiert. Die experimentellen Ergebnisse zeigen, dass die VPS-gespritzte Schicht eine höhere Verschleißfestigkeit aufweist als die HVOF-gespritzte Schicht. Der Verschleißmechanismus der VPS-gespritzten nanokristallinen Schicht kann als Kombination von Spanen und Pflügen charakterisiert werden. Für HVOF-gespritzte nanokristalline Schichten stellt sich der Verschleißmechanismus dagegen als Spanen mit partiellen Schichtablösungen dar. [source] Evaluation of Adhesion and Wear Resistance of DLC Films Deposited by Various MethodsPLASMA PROCESSES AND POLYMERS, Issue 6-7 2009Takahiro Horiuchi Abstract Diamond-like carbon (DLC) coatings are currently being used in a wide variety of industrial fields because of their outstanding properties, such as high hardness and low friction coefficient, among others. DLC coatings have various characteristics depending on the deposition method used. However, they have a problem regarding adhesion with the base material, which is a major factor hindering their expanded application in other fields. The adhesion of DLC coatings is generally evaluated using Rockwell indentation tests and scratch tests. These test methods induce damage in the specimen with the application of a single load. Accordingly, there is a problem of low correlation between such test results and evaluations of the adhesion of coatings on actual components that undergo repeated sliding cycles. With the aim of resolving that problem, this study evaluated the damage condition of three types of DLC coatings having different physical properties using newly devised cyclic sliding test methods involving the application of a continuously increasing load. The evaluation results obtained with these new methods differed from the results of Rockwell tests and scratch tests. These new test methods are more able to reproduce the damage done to DLC coatings in actual sliding cycles. This paper describes the test procedures and the evaluation results obtained. [source] Tribological behaviors of aligned carbon nanotube/fullerene-epoxy nanocompositesPOLYMER ENGINEERING & SCIENCE, Issue 8 2008Huan Wang The tribological properties of aligned CNT/fullerene-epoxy nanocomposites were studied by nanoscratch, nanowear, and nano-indentation tests. Compared with neat epoxy, aligned CNT/fullerene-epoxy nanocomposites showed lower friction coefficient in scratch tests, a reduction of 38.1 and 26.2%, respectively. In addition, the aligned CNT-epoxy composite showed better wear resistance and its hardness and Young's modulus increased by 29.4 and 16.8%, respectively. In contrast, for a fullerene-epoxy nanocomposite with 10 wt% fullerenes, the hardness decreased by 50% and the Young's modulus decreased by more than 60% when compared with the neat epoxy. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] | |||||||||||||