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Article
Wear Performance of a Laser Surface Hardened ASTM 4118 Steel
سلوك البلیان للفولاذ 4118 ASTM المصلد سطحیا باللیزر

Author: Assifa M. Mohamad
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2013 Volume: 31 Issue: 17 Part (A) Engineering Pages: 3235-3244
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

In this investigation ASTM 4118 steel was treated by using pulse Nd: YAGlaser with wave length 1064nm and pulse duration 100ns. In order to assess thenew tribological properties of laser surface hardened ASTM 4118 steel, the wearresistance between specimens treated with laser and those of conventionallyhardened under dry sliding conditions was compared. The change of wearmechanisms in laser hardened 4118 steel resulted in distinct difference in wearrates.The results showed that quenched zones not only had sufficient depth ofhardening and higher hardness, but had more retained austenite and finer carbidesbecause of a higher degree of carbide dissolution. Laser surface hardened ASTM4118 steel specimens exhibited superior wear resistance to their conventionallyhardened specimens due to the change in the microstructure hardening, highhardness. The wear mechanism for both the laser quenched layer andconventionally hardened layer was highly similar, generally involving adhesivewear mechanism , material transfer, wear induced oxidation and plowing. Also theresults of hardness show that increases with increasing of laser energy by 70%.


Article
Evaluation of surface roughness of composite according to surface treatment

Author: Sabah A Ismail
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2005 Volume: 5 Issue: 2 Pages: 174-179
Publisher: Mosul University جامعة الموصل

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Abstract

The purpose of this study was to evaluate the effect ofvarious finishing and polishing procedures on the surface roughness(Ra) of two composite resins: An organically modifiedceramic (Definite) and a micro hybrid (Tetric).Thirty specimens of each composite resin were fabricatedusing a stainless steel mold of 5 mm in diameter and 2 mmin depth. The composite resin was covered by a Mylar stripand pressed flat with a microscopic glass slide and light cured.The specimens for each composite resin were divided intothree groups, each of ten. The specimens in group one receivedno treatment, while the specimens in group two and threewere finished with diamond bur. After finishing with diamondburs group three were polished with Sof–Lex discs.The surface profile of the specimens was obtained with asurface profile–testing machine (Profilometer). The roughnessvalue in micrometer (μm) was recorded as the average Ra.Results showed higher surface roughness in groups finishedwith diamond burs followed by groups finished with diamondburs and polished with Sof–Lex discs while groups setagainst Mylar strip showed the lowest roughness values. Theresult revealed no significant difference in surface roughnessvalues between the two composite resins.


Article
Effect of laser surface treatment on the some of mechanical properties of AISI 4130 steel

Author: J.M. Taha
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2017 Volume: 35 Issue: 2 Part (B) Scientific Pages: 85-90
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

In this work the surface of an alloy of AISI 4130 steel is hardened by using CW Nd:YAG laser and then study the effect of laser surface hardening on mechanical properties such as yield strength (σy), ultimate tensile strength (σu.T.S), plasticity constant (k),strain hardening coefficient (n) , also evaluate the microstructure and microhardness during the hardening of the alloy. CW Nd:YAG laser was used to scan on the surface of samples by varying the laser beam energies (500,750,1000 mj) with travel speed 500 mm/min of the work table. There are many examinations were done for laser hardened of AISI 4130 steel such as an analysis of microstructure features by using an optical microscopy and microhardness. Also tensile test is carried out for the specimens before and after laser surface treatment. The results of this investigation showed that an improvement in mechanical properties after laser surface hardening, also microhardness decreases faraway the hardened surface toward the center of the specimen. While the microstructure examination showed that the laser energy 1000 mj lead to form fine plate martensite structure more than another energies 500 and 750 mj.


Article
An evaluation of the Effect of Surface Treatment On Amalgam Repair

Authors: Dr. Abdul Karim J. Al-Azzawi, B.D.S., M.Sc. د. عبد الكريم العزاوي --- Dr.Baidaa M. Zaidan, B.D.S., M.Sc. Prof. د. بيداء زيدان
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2008 Volume: 5 Issue: 4 Pages: 341-347
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The purpose of this in vitro study was to evaluate the effect of different surface treatments on shear bond strength of repaired amalgam using two types of amalgam. 120 acrylic blocks (2.7cm diameter by 2.0cm high) were constructed from cold cure resin, each one contained cylindrical hole (7mm diameter by 2mm high) on its circular face that filled with amalgam. The samples were divided into immediate repair group and delayed repair group, which was stored and incubated at 37C0 for one month. After aging the amalgam surface of delayed repair was finished with carbide bur and polished with abrasive rubber cup then divided into three groups according to the surface treatment that include group with out surface treatment, group roughened with diamond bur and the last group was abraded with aluminum oxide (50m) particles size, both immediate and delayed repair were further subdivided according to the type of amalgam used into three subgroups. The repair procedure was done by using a Teflon split mold which containing an opening (3mm diameter by 5mm high) then all the samples were storage and incubated at 37C0 for one week prior to testing.Testing was done by applying shear force at the interface between the initial and repair amalgam with special designed chisel shape rod by using Zwick testing machine at across head speed of 5mm/min.Analysis of the results showed that the shear bond strength in immediate repair were significant higher than of delayed repair and the group roughened with diamond bur is higher than group treated with aluminum oxide and untreated group.The shear bond strength of delayed repair of amalgam is less than that of immediate repair, the surface produced by roughening the samples with a diamond bur will give best strength than the surface treated by aluminum oxide and untreated surface (smooth surface) and the same types of amalgam restorations used in amalgam repair gave better result than different type of amalgam.


Article
Effect of glass fiber reinforcement surface treatment on the soft liner retention and longevity

Authors: Inas Abdul-Sattar ايناس عبد الستار --- Nabeel Abdul-Fattah نبيل عبد الفتاح هاطور
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2012 Volume: 24 Issue: 3 Pages: 8-12
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Denture liners have been used in dentistry for many years. Soft denture liner is one of the denture linerswhich used to enhance the fit of poor fitting dentures and prevent trauma to sensitive mucosa. One of thedisadvantages of the soft denture liner is the frequent debonding from the denture during clinical use thus reducingthe longevity of such prosthesis. Glass fibers integrated at or on the fitting surface of the denture used to improve thebonding of the silicone soft liner to the acrylic surface.Materials and methods: the shear bond strength calculated to evaluate the effect of the glass fiber surfacetreatment on the bonding between the acrylic surface and the silicon soft liner. 120 samples were prepared anddivided into 3 major groups: Group I for the conventional heat cure acrylic, Group II for the pour acrylic and Group IIIfor the light cure acrylic. Each one of these major groups divided into 2 subgroups, the first one for the Mollosil siliconsoft liner and the second one is for the Molloplast-B silicon soft liner. Each one of these sub groups consist of 2 types ofthe acrylic surface: smooth (control) and glass fiber net surface treatment.Results: this study revealed that some types of the surface treatment exhibited a highly significant improvement in thebonding between the acrylic surface and the soft liner.Conclusion: glass fiber surface treatment could improve the bonding between the acrylic surface and the soft liner


Article
Microhardness and Tension Measurements of Pulsed-Laser Surface-Treated Aluminum Alloys

Authors: Farah A. Hattab --- Esraa K. Hamed --- Suad M. Kadhim --- Aseel A. Shakaty
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2015 Volume: 11 Issue: 3 Pages: 21-24
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

In this research, pulsed Nd:YAG laser with wavelength of 532nm and pulse duration of 100ns at different energies (700, 800, 900 and 1000 mJ) and spot size of 1.5 mm was used to treat surfaces of different aluminum alloys. These alloys are [Al-Cu-Mg], [Al-Mg-Mn] and [AL-Zn-Mg] and [Al-Si-Mg]. The effects of laser energy on the microhardness and tensile measurements of the used aluminum alloys were studied.


Article
SURFACE LAYERS CHARACTERISTICS OF THREE DIFFERENT STEEL ALLOYS HARDENED BY ND: YAG LASER
خواص الطبقات السطحية لثلاث انواع مختلفة من سبائك الفولاذ المصلدة بالليزر نيديميوم – ياك

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Abstract

Laser surface treatment is an effective way to improve the characteristics of surface layers for the most alloys. In the present work, three different steel alloys: low carbon steel A3115, medium carbon steel 1045 and high carbon steel 52100 were hardened by Nd: YAG laser at 1.064nm wave length with 1000mj energy. An experiments with Nd: YAG laser were carried out to study the effect of laser hardening process on the microstructure, roughness, microhardness during laser hardening of the three alloys. All of surface layers characteristics were analyses using optical microscope. Laser surface treatment enhanced the characteristics of surface layers for all the alloys. Also Nd: YAG laser surface treatment produced plate martensite for 52100 alloy more than A3115 and 1045 alloys. From the results is obtained finer martensite, an excellentroughness and larger microhardness for this alloy. The aim of present investigation study the effect of Nd: YAG laser hardening on the characteristics of surface layers for three different steel alloys (A3115, 1045, 52100) .

تعتبر المعاملة السطحية بالليزر من الطرق الفعالة في تحسين خواص الطبقات السطحية لأغلب السبائك . في البحث الحالي تم تصليد ثلاث انواع مختلفة من سبائك الفولاذ: فولاذ منخفض الكاربون ,A3115 فولاذ متوسط الكاربون 1045 والفولاذ العالي الكاربون 52100 بالليزر نيديميوم– ياك ذو الطول الموجي 1.064nm وبطاقة .1000mj اجريت تجارب باستخدام الليزر نيديميوم – ياك لدراسة تأثير عملية التصليد بالليزر على البنية المجهرية, الخشونة, الصلادة الدقيقة اثناء التصليد بالليزر للسبائك الثلاثة . تم دراسة معظم خواص الأسطح للسبائك باستخدام المجهر الضوئي . اظهرت المعاملة السطحية بالليزر الى زيادة خواص الطبقات السطحية ولجميع السبائك, كذلك أدت المعاملة السطحية بالليزر إلى تكوين مارتنسايت رقائقي للسبيكة52100 اكثر نعومة مما هو عليه للسبيكتين .1045,A3115 من النتائج تم الحصول على أفضل خشونة وأعلى صلادة دقيقة لنفس السبيكة . الهدف من البحث الحالي هو دراسة تأثير التصليد بالليزر نيديميوم – ياك على خواص الطبقات السطحية لثلاث سبائك مختلفة من الفولاذ ( .( 52100, 1045, A3115.


Article
Non-polar micro-coating on acrylic denture material for reducing the incidence of dental biofilm formation

Authors: Dr. Lateef Essa Aljorani د.لطيف عيسى الجوراني --- Dr. Arshad F. Jassem Al-Kaabi ارشد جاسم
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2018 Volume: 15 Issue: 1 Pages: 77-82
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Aim: Dental plaque formation is a major health risk associated with prolonged wornacrylic dentures. The dental biofilm usually develops when improper cleaning andsterilizing of dentures is achieved. The aim of this study was to improve theacrylic material surface properties for minimizing the incidence of dental plaqueformation on acrylic dentures by lowering the surface energy.Method: The acrylic (polymethylmethacryate) surface modification was achieved byapplying a non-polar micro-coating on acrylic samples which was the dentalbaseplate wax. Two experimental groups used in this study, the control and thecoated groups with 10 samples each. The surface analysis was conducted using thecontact angle's technique. All samples soaked in salivary solution for 5 days. Themethylene blue dye material used as an indicative for the dental plaque formation.Results and conclusion: The surface analysis showed a significant decrease in thesurface hydrophilicity of the coated group by increasing the water contact angledegree values (P-value<0.05). The microscopic analysis by visual inspectionshowed a reduced formation of the dental biofilm on the acrylic samples. Withinthe limitations of this study, the suggested coating material can possibly reducethe incidence of the dental biofilm formation on acrylic dentures.


Article
Effect of various surface treatment procedures on shear bond strength of stainless-steel orthodontic brackets to composite resin

Author: Bayan A Hassan
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2018 Volume: 18 Issue: 1 Pages: 21-30
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: The aim of this study was to evaluate the shear bond strength of brackets bonded to composite restorations using four types of surface conditioning procedure. Materials and Methods: Thirty two cylindrical cavities were made at the center of self-cured acrylic resin blocks. All cavities were then filled with composite resin. The specimens were randomly divided into four groups. Group one: Composite surface was acid etched with 37% phosphoric acid. Group two: After using 37% phosphoric acid, bonding agent was applied and cured. Group three: After using 37% phosphoric acid silane coupling agent was applied then bonding agent was applied. Group Four: The composite surface roughened with a diamond bur, and then 37% phosphoric acid was applied. Brackets were bonded onto the composite prepared samples with Transbond XT. Shear Bond Strength was measured by a universal testing machine. KruskalWallis test was utilized for data analysis. Results: There was a significant difference between the four groups. The highest bond strength was that of Group 3. Group 1 had the lowest bond strength. Conclusions: Roughening the composite surface before acid etching was effective to improve the bond strength of orthodontic brackets to composite restorations. Addition of silane before bonding agent application result in highest bond strength.


Article
Surface Treatment of Aluminum Alloys Using Nd:YAG Laser

Authors: Majid Hammed Ismaiei --- Mohamed Abdul Wahhab
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2011 Volume: 29 Issue: 14 Pages: 3006-3018
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

In this research, a pulsed Nd:YAG laser with wavelength (1064nm )and (532 nm) and pulse duration (100 ns) for different energies [250 mJ,500 mJ,750 mJ,1000 mJ ] and spot size (1.5mm) was used.Laser surface treatment is the most important way in industrial application because of its ability to improve the surface properties of metal and alloys. The alloys used were [Al-Cu-Si], [Al-Si-Mg] and [AL-Zn-Mg].The essential aim for this work includes study the effect of laser parameters on aluminum alloys. In laser surface engineering the mirohardness and wear tests will be studied after laser treatment.The effect of laser parameters includes:1- The effect of the pulsed Nd: YAG laser energy.2- The effect of the number of shots (pulse).

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