scholarly journals Electroless Ni-P Coatings: Preparation and Evaluation of Fracture Toughness and Scratch Hardness

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Wagner Sade ◽  
Reinaldo Trindade Proença ◽  
Thiago Daniel de Oliveira Moura ◽  
José Roberto Tavares Branco
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Chemical Composition ◽  
Scratch Hardness ◽  
Hard Particles ◽  
Steel Aisi ◽  
Electroless Ni ◽  
Preparation And Evaluation ◽  
Phase Relationships ◽  
Thermally Treated

Ni-P chemical coatings have been used to prevent wear, corrosion and as an alternative for hard chromium, since the latter's deposition processing is very harmful to the human health and the environment. In the present paper, Ni-P coatings with 8 and 10% P were deposited in steel AISI 1020 and thermally treated. Ni-1wt%P coatings with incorporation of hard particles of Al2O3 were also investigated. The microstructure and phase relationships were analyzed and correlated with the fracture toughness and scratch hardness of the coatings.The results show that the fracture toughness of the coating was smaller when thermally treated at 400°C for 1 hour and the scratch hardness reached a peak in this temperature. The relation of chemical composition and microstructure with mechanical properties of Ni-P coatings is presented. The phosphorus contents, the crystallization, and the incorporation of hard particles in the coatings change the values of toughness fracture and scratch hardness.

Mechanical Properties of α- and β-SiAlON Composite Ceramics Using β-SiAlON Powder

2008 ◽  
Vol 403 ◽  
pp. 111-114 ◽  
Author(s):  
Kei Asakoshi ◽  
Junichi Tatami ◽  
Katsutoshi Komeya ◽  
Takeshi Meguro ◽  
Masahiro Yokouchi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Rare Earth ◽  
Chemical Composition ◽  
Metal Oxides ◽  
Bending Strength ◽  
Rare Earth Oxide ◽  
Composite Ceramics ◽  
Oxide Powders ◽  
Sialon Powder

β-SiAlON powder was used as a raw powder to fabricate α/β-SiAlON composite ceramics with different rare earth elements. The phases present in the sample fabricated from -SiAlON, α-Si3N4, AlN, and rare earth oxide powders were - and -SiAlONs. The composition was dependent on the chemical composition and firing profile. The sample obtained by adding Yb2O3 had a high -SiAlON content. The /-SiAlON composite ceramics had high densit. Their microstructures depended on the used metal oxides, namely, the addition of Nd2O3 and CaCO3 resulted in the elongation of the -SiAlON grains. The bending strength, fracture toughness, and hardness were influenced by the -SiAlON content, amount of elongated grains, and density of the sample.

Age-Related Changes in Structure, Composition and Mechanical Properties of Swine Cortical Bone

2009 ◽  
Author(s):  
Liang Feng ◽  
Rohit Bhargava ◽  
Iwona Jasiuk
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Chemical Composition ◽  
Bone Structure ◽  
Experimental Methods ◽  
Biological Processes ◽  
Age Related ◽  
Open Question ◽  
Age Related Changes ◽  
Comprehensive Study

Bone has a complex hierarchical structure spanning from nanometer to macroscopic dimensions. We apply several experimental methods at different structural scales to study the three fundamental aspects of this material: the structure, composition and mechanical properties. As a biological material, bone is constantly under development. These biological processes such as remodeling and aging are known to increase the susceptibility of bone to fracture. The age-related changes in the fracture toughness and other mechanical properties are manifested by the alteration of the bone structure and chemical composition [1]. Various studies addressed the changes in bone’s structure, composition and mechanical properties due to aging [2–5]. However, these studies were confined to only one or two of these aspects, separately. So there is still an open question about how these three aspects are correlated with each others. Thus, a comprehensive study is needed to address it.

Methodology for Vintage Pipelines Assessment

2012 ◽  
Author(s):  
Mélissandre Phelippon ◽  
Stéphane Hertz-Clemens ◽  
Philippe Notarianni
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Chemical Composition ◽  
Sulfur Content ◽  
Parent Material ◽  
International Standards ◽  
Composition Analysis ◽  
Line Pipe ◽  
Test Pieces ◽  
Chemical Composition Of Steel

During inspection and maintenance operations, pipeline operators may encounter pipes showing incomplete records. However, data such as pipe tensile properties and toughness are essential to perform a realistic pipeline fitness for service analysis. These situations most often occur with older pipelines, in a period where line pipe quality control and quality assessment were not as stringent as today. In order to avoid a cut and a replacement of the pipe, introducing transit interruption and high expenses for the operator, a methodology for determining mechanical properties has been developed. The methodology described in this paper relies on data obtained from many tests performed on this specific type of line. The study and analysis of these database information led to working out correlations between parameters measured on field, and missing recorded mechanical properties. The first data that can be obtained quite easily is the chemical composition of steel, which can be analyzed in a laboratory from samples directly removed from parent material of the line pipe. Using the result of the previous analyses, the following correlations have been determined from the database information, and have been compared to correlations given in international standards (API 579, BS7910,…): - Charpy V energy measured at 0°C versus Charpy U energy pleasured at 20°C, - Charpy V energy versus sulfur content, - Fracture toughness versus Charpy V energy, - Fracture toughness versus sulfur content. A practical experiment of these results have been performed, as chemical composition analysis from samples were made on 5 removed test pieces issued from line pipes. These tests aimed at comparing the results given by correlations with the mechanical properties of the line pipes, and validating the feasibility of this methodology on the field. At the same time, database information was also used to check the theoretical behavior of parent metal regarding to the design temperature, by using a relation between steel toughness value, and its transition temperature at 28 J, issued from toughness transition curves.

Relations between chemical changes and mechanical properties of thermally treated wood 10th EWLP, Stockholm, Sweden, August 25–28, 2008

Holzforschung ◽  
2009 ◽  
Vol 63 (6) ◽  
Author(s):  
Elisabeth Windeisen ◽  
Helmut Bächle ◽  
Bernhard Zimmer ◽  
Gerd Wegener
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Fagus Sylvatica ◽  
Treated Wood ◽  
Strength Properties ◽  
Thermal Treatments ◽  
Chemical Changes ◽  
Stable Compound ◽  
Temperature Load ◽  
Thermally Treated

Abstract Thermal treatments of wood (Fagus sylvatica and Fraxinus excelsior) were examined. The temperature load on wood causes characteristic changes in the chemical composition, which were determined by means of several defined methods. The results confirm that in addition to the degradation of polyoses lignin, known as the thermally most stable compound, also shows significant thermal alterations. In addition, mechanical properties of the specimens were examined in order to correlate these results with the effects of chemical changes of thermally treated wood. It was shown, e.g., that the decomposition of the polyoses can affect the strength properties both positively and negatively.

Microscratch Test for Ultra-Thin Films

1990 ◽  
Vol 188 ◽  
Author(s):  
T. W. Wu
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Acoustic Emission ◽  
Critical Load ◽  
Normal Load ◽  
Tangential Load ◽  
Scratch Hardness ◽  
Deposited Films ◽  
Microscratch Test

ABSTRACTIn a microscratch test performed by using an upgraded microindenter, the normal load, tangential load, scratch length and acoustic emission, are monitored simultaneously during an entire scratch process for the purposes of measuring the critical load and studying the ffilure mechanisms of the deposited films. The adhesion strength, scratch hardness, fracture toughness and friction are the mechanical properties which are possible to obtain by using this technique. Results from aluminum, carbon and zirconia coatings will be discussed.

Microstructural and fractographic characterization of B4C-Al cermets tested under dynamic and static loading

1989 ◽  
Vol 47 ◽  
pp. 562-563
Author(s):  
Gyeung Ho Kim ◽  
Mehmet Sarikaya ◽  
D. L. Milius ◽  
I. A. Aksay
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Static Loading ◽  
Carbon Deposition ◽  
Full Density ◽  
Unique Combination ◽  
Strong Component ◽  
Reaction Products

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.

Characterization of interfaces in CVD-coated nicalon fiber-reinforced SiC

1989 ◽  
Vol 47 ◽  
pp. 556-557
Author(s):  
K.L. More ◽  
R.A. Lowden
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Frictional Stress ◽  
Fiber Reinforced ◽  
Pull Out ◽  
Carbon Coated ◽  
Fiber Matrix

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.

Study of the character and causes of destruction of the cardan shaft of the propeller engine

2019 ◽  
Vol 85 (12) ◽  
pp. 43-50
Author(s):  
D. A. Movenko ◽  
L. V. Morozova ◽  
S. V. Shurtakov
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Yield Point ◽  
Protective Coating ◽  
Fracture Pattern ◽  
Corrosion Cracking ◽  
Tempered Martensite ◽  
Neck Formation ◽  
Static Mechanism ◽  
Shaft Surface

The results of studying operational destruction of a high-loaded cardan shaft of the propeller engine made of steel 38KhN3MFA are presented to elucidate the cause of damage and develop a set of recommendations and measures aimed at elimination of adverse factors. Methods of scanning electron and optical microscopy, as well as X-ray spectral microanalysis are used to determine the mechanical properties, chemical composition, microstructure, and fracture pattern of cardan shaft fragments. It is shown that the mechanical properties and chemical composition of the material correspond to the requirements of the regulatory documentation, defects of metallurgical origin both in the shaft metal and in the fractures are absent. The microstructure of the studied shaft fragments is tempered martensite. Fractographic analysis revealed that the destruction of cardan shaft occurred by a static mechanism. The fracture surface is coated with corrosion products. The revealed cracks developed by the mechanism of corrosion cracking due to violation of the protective coating on the shaft. The results of the study showed that the destruction of the cardan shaft of a propeller engine made of steel 38Kh3MFA occurred due to formation and development of spiral cracks by the mechanism of stress corrosion cracking under loads below the yield point of steel. The reason for «neck» formation upon destruction of the shaft fragment is attributed to the yield point of steel attained during operation. Regular preventive inspections are recommended to assess the safety of the protective coating on the shaft surface to exclude formation and development of corrosion cracks.

Sign in / Sign up

Export Citation Format

Share Document