Ağır Araç Fren Balatalarında Katı Yağlayıcıların Deney Tasarımı Tabanlı İncelenmesi

Öz

Ağır hizmet araçları için fren balatası formülasyonlarının, aşırı frenleme koşulları altında aşınma direnci, fade direnci ve sürtünme kararlılığı arasında bir denge sağlaması gerekmektedir. Bu çalışma, grafit, antimon trisülfür (Sb₂S₃), molibden disülfür (MoS₂), çinko sülfür (ZnS) ve kalsiyum florür (CaF₂) içeren katı yağlayıcı bileşimlerinin bakır içermeyen fren balatalarının tribolojik performansı üzerindeki etkisini sistematik olarak incelemektedir. Çalışmada, bu yağlayıcıların sürtünme katsayısı, aşınma oranı ve fade direnci üzerindeki etkisini değerlendirmek için Deney Tasarımı (DOE) yöntemi uygulanmış ve testler ECE R90 koşulları altında Krauss tipi sürtünme test cihazı kullanılarak gerçekleştirilmiştir.Elde edilen bulgular, CaF₂’nin sürtünme katsayısını önemli ölçüde artırdığını, Sb₂S₃’ün fade direncini iyileştirdiğini ancak aşınma oranını da artırdığını göstermektedir. Grafitin ise fade direnci veya sürtünme kararlılığı üzerinde belirgin bir etkisi olmadan aşınma kaybını azalttığı belirlenmiştir. Genel Faktöriyel Regresyon ve Varyans Analizi (ANOVA) sonuçları, MoS₂ ve Sb₂S₃’ün fade direnci üzerinde en etkili faktörler olduğunu, grafitin ise aşınma kaybını azaltmada baskın rol oynadığını ortaya koymuştur. Bu çalışma, ağır hizmet uygulamaları için üstün frenleme performansı sağlamak amacıyla optimize edilmiş çok bileşenli metal sülfür formülasyonlarının gerekliliğini vurgulamaktadır. Özellikle MoS₂ ve Sb₂S₃ içeren sinerjik yağlayıcı kombinasyonlarının tribofilm kararlılığını artırarak fren balatalarının dayanıklılığını iyileştirdiği gösterilmiştir. Gelecekteki araştırmalar, bu bileşimlerin daha da optimize edilmesine ve gerçek dünya frenleme koşulları altında uzun vadeli performanslarının detaylı olarak incelenmesine odaklanmalıdır.

Anahtar Kelimeler

• Fren balataları
• katı yağlayıcılar
• triboloji
• sürtünme
• ANOVA

A Design of Experiments-Based Investigation of Solid Lubricants in Heavy Vehicle Brake Pads

Öz

Brake pad formulations for heavy-duty vehicles must balance wear resistance, fade resistance, and friction stability under extreme braking conditions. This study systematically investigates the impact of solid lubricant compositions, including graphite, antimony trisulfide (Sb₂S₃), molybdenum disulfide (MoS₂), zinc sulfide (ZnS), and calcium fluoride (CaF₂), on the tribological performance of copper-free brake pads. A Design of Experiments (DOE) approach was employed to develop 29 unique formulations and evaluate them under the ECE R90 test procedure using a Krauss friction tester. Statistical analyses were used to determine the effects of lubricant combinations on performance metrics. The findings revealed that increasing CaF₂ content led to a significant rise in the coefficient of friction (up to 0.46), whereas Sb₂S₃ enhanced fade resistance by reducing loss of friction coefficient to as low as 0.03 but increased wear. MoS₂ was associated with superior thermal stability, while graphite primarily contributed to reduced wear loss (minimum 0.009 g). The formulation containing 10 wt% graphite, 2.5 wt% MoS₂, and 2.5 wt% CaF₂ demonstrated the most optimal balance of performance. These results underscore the importance of synergistic solid lubricant combinations in improving the durability and effectiveness of environmentally friendly brake pad formulations for heavy-duty applications.

Anahtar Kelimeler

• Brake pads
• solid lubricants
• tribology
• friction
• ANOVA

Kaynakça

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