Geri Dön

ZrB-ZrBN çok katlı kaplamaların korozyon davranışı

Başlık çevirisi mevcut değil.

  1. Tez No: 55930
  2. Yazar: O.LEVENT ERYILMAZ
  3. Danışmanlar: DOÇ.DR. MUSTAFA ÜRGEN
  4. Tez Türü: Yüksek Lisans
  5. Konular: Metalurji Mühendisliği, Metallurgical Engineering
  6. Anahtar Kelimeler: Belirtilmemiş.
  7. Yıl: 1996
  8. Dil: Türkçe
  9. Üniversite: İstanbul Teknik Üniversitesi
  10. Enstitü: Fen Bilimleri Enstitüsü
  11. Ana Bilim Dalı: Belirtilmemiş.
  12. Bilim Dalı: Belirtilmemiş.
  13. Sayfa Sayısı: 61

Özet

ÖZET Zr-B ve Zr-B-N kaplamalar sundukları renkler sayesinde dekoratif kaplamalar grubuna yeni katılan kaplamalardır. Zr-B kaplamalar aşınmaya olan dirençleri ve renklerinin bozulmaması açılarından dekoratif amaçlara uygun bir kaplama gibi gözükse de kaplama yüzeyindeki mikro ve makro hatalardan dolayı taban malzemeyi korozyondan korutucu özelliğe sahip değildir. Zr-B-N kaplamalarda zaman içerisinde NaCl içeren ortamlarda renklerinin bozulması sebebiyle dekoratif amaçlara pek uygun olmamakla birlikte korozyona karşı koruyucu niteliği ve yapışma özeliği Zr-B kaplamalara göre çok daha iyidir. Çok katlı kaplamalar ile Zr-B kaplamaların renk ve aşınma özellikleri ile Zr-B- N kaplamaların daha iyi olan koruyucu özellikleri ve iyi yapışma özelliklerini birleştirmek mümkün olabilir. Ayrıca çok katlı kaplamalarda tek katlı kaplamalarda gözlenen tabana ulaşan hatalarda bir azalma beklenebilir. Bu düşünceden yola çıkarak çelik malzeme üzerine (Zr-B-N + Zr-B + Zr-B-N + Zr-B ) reaktif ve reaktif olmayan d.c. manyetik sıçratma yöntemi ile çok kath(2, 4, 8, 16) ve tek katlı Zr-B-N, Zr-B kaplamalar üretilmiştir. Üretilen numunelere elektrokimyasal deneyler (İN H2SO4 ve %3.5 NaCl çözeltileri içinde), tuz püskürtme deneyleri, dekorasyon deneyleri, kalınlık ölçüm deneyleri, dinamik mikrosertlik deneyleri, çizik deneyleri uygulanmıştır. Yapılan deneyler sonucunda çok katlı kaplamalarda katman sayısının artışı korozyon özelliklerini iyileştirmektedir. Fakat tek kath kaplamalarda gözlenen makro hataların çok katil kaplamalarda giderilmesi mümkün olamamıştır. Çok katil kaplamalarda Zr-B kaplamaların sertlik, aşınma dayanımı ve renk özellikleri ile Zr-B- N kaplamaların iyi yapışma özellikleri birleştirilebilmektedir.

Özet (Çeviri)

SUMMARY CORROSION BEHAVIOR OF ZIRCONIUM BORON NITRIDE AND ZIRCONIUM BORIDE MULTEAYER COATED STEELS Hard, wear resistant coatings which are deposited by Physical Vapour Deposition (PVD) techniques are generally applied to provide a surface having other beneficial properties such as wear resistance, corrosion protection, optical and electrical properties and decorative appearance. These coatings are mainly based on carbides, nitrides and borides of the transition metal elements. PVD processes can be divided into two groups according to generation of vapour: evaporation and sputtering. Evaporation is the oldest and the simplest PVD method. Material to be deposited is placed in a boat or crucible and then heated resistively or by the high current electron beam or laser beam or arc. In all cases the material evaporates and form a vapour flux in the vacuum chamber. Condensation of this vapour onto the substrate produces the desired film. When the surface of a material is bombarded with high energetic particles, generally ions, the physical erosion of the material from the surface is occured. This effect is known as sputtering. Sputtering is widely used as a source of vapour for thin film deposition. In all sputtering PVD processes the ions for sputtering is produced by glow discharge plasma. Introducing of reactive gas/gases into the chamber while depositing thin films causes compound film formation onto the substratewbich is called as reactive PVD. XIIonizing the vapour to be deposited and applying negative potential (BIAS) to the substrate relative to the vacuum chamber walls is named as ion plating. Ion plating improves the film properties - such as adhesion, the increase of film density - and deposition rate. All thin film processes contain four sequential steps. A source of film material is provided, the material is tranported to the substrate, deposition takes place and finally it is analyzed to evaluate the process. The results of the analysis are then used to adjust the conditions of the other steps for the film property modification. Because of the interesting colors of many thin films (such as carbides, nitrides and borides of the transition metal elements) produced by PVD technique, decorative applications of this type of coatings are available. These films give not only interesting colors but also wear resistance, ease of changing color and reproducibility of the film. Currently, the primary deposited decorative coatings are usually based on nitrides or carbonitrides of titanium and titanium alloys with an essentially limited spectrum of color tones. Borides such as LaB6, Zr-B and Zr-B-N coatings gives wide range spectrum of color tones. There is two main applications of ZrB2 coatings: wear-resistant coatings on cutting tools and their use of photothermal absorbers. The use of Zr-B coatings for decorative purposes is new. Zr-B and Zr-B-N coating are produced employing non- reactive as well as reactive d.c. magnetron sputtering deposition technique. Zr-B coatings show very dense film structure. The addition of nitrogen to Zr- B coating changes the structure of film from cyristalline to amorphhous. The increase of nitrogen addition decreases the hardness and deposition rate of the film. The color of Zr-B coating is silver grey. The addition of nitrogen changes the color silver grey to dark grey, intense black and, in transforming to amorphous structure, the color changes to gold with red and green interference colors. The substrate temperature and the BIAS voltage have only little effect on the color and xnbrilliance: increasing the temperature and decreasing the BIAS voltage result in a smooth surface. However these changes are not detectable by human eye. The corrosion properties of Zr-B and Zr-B-N coatings are play an important role for decorative application of these coatings. In previous studies, the electrochemical and decoration experiments showed that the corrosion protection of Zr-B and Zr-B-N coatings depended on their porosity. In Zr-B-N coatings the main sources of porosity were indentified as macro defects such as droplet peripheries and craters. Zr-B coatings which were less adherent had also inherent porosity. Zr-B-N coatings showed better corrosion protection properties than to Zr-B coatings. The results salt spay tests conducted on Zr-B and Zr-B-N coated steels showed that because of defective nature of coatings they were not capable of protecting the substrate. The corrosion resistance of Zr-B- N coatings was worse than Zr-B. Zr-B-N coatings failed owing to decomposition, with color changes and a marked decrease in birilliance. Amorphous Zr-B-N films with high nitrogen contents offer interesting interference colors, but their application is restricted, owing to their limited corrosion resistance and hardness. Multilayer Zr-B and Zr-B-N coatings may combine good properties (such as adhesion and more protective properties of Zr-B-N coatings and stability and hardness of Zr-B coatings) of each coating. It may also eleminate macro and micro defects of this type of single layer coatings. Considering the above approaches, in this study, corrosion behaviour of multilayer (2, 4, 8, and 16) magnetron sputtered Zr-B-N + Zr-B coatings on carbon steel substrates were investigated and compared with single layer Zr-B and Zr-B-N coated samples. Potentiodynamic polarization and salt spray testing were used. Copper decoration technique was employed for the determination of defects and pores extending through the coating. The adhesion, thickness and hardness of the coating were also characterized. The major aim of calotest was to determine the coating thickness. Furthermore, results of calotest experiments had shown that this test also gives valuable information about the adhesion of coatings. Investigation of the callote xuiregion showed that during grinding of the coating, loss of adhesion had taken place in single layer Zr-B, 2, 4 and 8 layered coated samples. The results of dynamic micro hardness experiments showed that there was a big diffrence between hardness of single layer Zr-B coating (46950 N/mm2) and single layer Zr-B-N coating(16344 N/mm2).The hardness of the multilayer samples was between single layer Zr-B and Zr-B-N. The increase of layers caused the decrease of hardness values until reaching to a plateu value. The scratch test results were not meaningful because of the low hardness of the substrate material. To get a consistent results, a controlled load was applied with Rockwell C diamond tip, to the coated samples without moving the table. The results were more meaningful than scrath test results. The starting load of accustic emission signals which »identifies the cracks of the surface, were lower in Zr-B than Zr-B-N coatings. In higher loads the number of accustic emission signals were higher in Zr-B-N than Zr-B coatings. However the amplitude of accustic emission were lower in Zr-B-N than Zr-B coatings signals Multilayer coatings could not eliminate totally the formation of defects on coating which joined the substrate to the environment, hence the polarization behavior of multilayer coatings in acid solutions reflected the polarization characteristics of substrate with only decreased critical and passive current densities. However, multilayer coatings decreased the number of active sites. Results of the anodic polarization experiments conducted in 3.5% NaCl solution had shown that both single layer Zr-B and Zr-B-N coatings and multilayer coatings improved the pitting behavior of the substrate. However, as the experiments conducted in sulfuric acid previously showed, because of the defective nature of the coating, the elimination of pitting was not possible. The pitting potentials of all the coated samples were close to each other within 60 mV (between -480 - -540 mV). In multilayer coated samples a clear improvement of the pitting behavior was not observed with the increase of the number of layers. These results are not surprising while the material that was subjected to pitting in all cases was the substrate material (carbon steel) that is exposed to the corrosive medium through defects and pores in the coating xrvThe results of salt spray tests had indicated that a definite increase in corrosion resistance of samples with the increase of the number of layers Moreover in 2 and 4 layered samples, large bare areas around corrosion sites were observed which indicated that due to undermining effect of corrosion, the coating was disbonded from the surface. In 8 and 16 layered samples corrosion was observed, only around some of the macro defects. These macro particles were probably extending through the entire coating. Disbonding of coating around the corrosion sites were not observed in these samples. These results showed that the number of defect sites extending through the coating as well as the adhesion of the coating to the substrate played an important role in the extension of corrosion damage. xv

Benzer Tezler

  1. Tez No

    451806

    Orta gelir tuzağını aşmada sektörel dönüşüm rotasının belirlenmesi: Türkiye için ampirik analiz

    Identifying the sectoral transformation route in order to overcome the middle income trap: Empirical analysis for Turkey

    ONUR ÇAĞLAR

    Yüksek Lisans

    Türkçe

    Türkçe

    2016

    EkonomiBülent Ecevit Üniversitesi

    İktisat Ana Bilim Dalı

    PROF. DR. HAMZA ÇEŞTEPE

  2. Tez No

    801090

    Türkiye'de gerçekçi matematik eğitimi ile ilgili yapılan lisansüstü tezlerin incelenmesi

    Examination of graduate thesis on realistic mathematics education in Turkey

    ALİ İBRAHİM YETİMAKMAN

    Yüksek Lisans

    Türkçe

    Türkçe

    2023

    Eğitim ve ÖğretimMarmara Üniversitesi

    Matematik ve Fen Bilimleri Eğitimi Ana Bilim Dalı

    PROF. DR. AHMET ŞÜKRÜ ÖZDEMİR

  3. Tez No

    765362

    Synthesis of pyrrole-imine Schiff base ligands and their complexes with group IVB metal (Ti, Zr, Hf)

    Pirol-imin Schiff bazı ligandlarının sentezi ve grup IV metalleri ile kompleksleri (Ti, Zr, Hf)

    BERKAY ŞAHİN

    Yüksek Lisans

    İngilizce

    İngilizce

    2022

    Kimyaİstanbul Teknik Üniversitesi

    Kimya Ana Bilim Dalı

    PROF. DR. OZAN SANLI ŞENTÜRK

  4. Tez No

    143669

    Production and development of bulk metallic glasses

    İri ve hacimli metalik cam malzemelerin üretimi ve geliştirilmesi

    KAAN PEHLİVANOĞLU

    Doktora

    İngilizce

    İngilizce

    2003

    Metalurji MühendisliğiOrta Doğu Teknik Üniversitesi

    Metalurji ve Malzeme Mühendisliği Ana Bilim Dalı

    PROF. DR. VEDAT AKDENİZ

    PROF. DR. ŞAKİR BOR

  5. Tez No

    879512

    Alüminyum esaslı zirkonyum diborür takviyeli fonksiyonel derecelendirilmiş kompozitlerin üretimi ve karakterizasyonu

    Production and characterization of functional grading aluminum based zirconium diboride reinforced composites

    SERCAN TÜRE

    Yüksek Lisans

    Türkçe

    Türkçe

    2024

    Gemi MühendisliğiYıldız Teknik Üniversitesi

    Gemi İnşaatı ve Gemi Makineleri Mühendisliği Ana Bilim Dalı

    PROF. DR. ÖMER SAVAŞ

Geri Dön