How It Works: Vapor Deposition Process | Pure Glass Technology | Corning

通过这种看似与玻璃无关的制造工艺,康宁生产出了全世界最纯净的玻璃。

气相沉积是一种高温工艺,通过在生长表面上沉积一层又一层微小的玻璃颗粒来制造玻璃,而不是冷却熔融液体。

气相沉积是康宁在光纤领域取得世界领先地位的关键。康宁还采用此工艺生产其他先进玻璃技术产品,如精密的望远镜反射镜。

这来自于康宁丰富的材料知识、工艺控制专业知识、尖端设备设计和自动化技术的经典组合。

工作原理

此工艺包括多种形式,但康宁最常用的是外部气相沉积 (OVD),它可以在固态基质顶部(或周围)以极小的薄层"制作"新的玻璃。

例如,制造光纤时,从含硅(有时还包含被称为“掺杂剂”的受控添加剂)的液体中生成蒸汽。燃烧过程将产生极小的氧化玻璃颗粒(被称为“烟灰”)和未燃烧蒸汽的混合物。蒸汽转而会凝结在颗粒周围,然后进一步聚集,粘附在基质上。

蒸汽严密地沉积在长长的陶瓷饵杆周围。一层又一层的蒸汽与玻璃微粒产生反应,最终形成超纯净的玻璃。取下饵杆后,完美的玻璃管(被称为“预制棒”)将在极高温度下被压实,并拉制成细如发丝的光纤。 

对于镜头、反射镜和多年来美国宇宙飞船用的玻璃舷窗,气相沉积直接发生在玻璃制造过程中,然后形成庞大、密实的整块玻璃。制造大型望远镜反射镜可能需要超过一年时间。

为什么重要

对于光纤和望远镜镜头之类的产品,玻璃不能包含任何有碍光透射的污染物,哪怕是最小的污染物。气相沉积能够严格控制可能进入蒸汽,进而融入玻璃的化学物质。最终制造出能够想象的最纯净、具有非凡适用性的玻璃。

观看下方视频,了解气相沉积工艺的工作原理。

Why it's important

For products like optical fiber and telescope lenses, glass must be free of even the smallest contaminants that could interrupt transmission of light. OVD-formed glass allows very tight control of the chemicals that go into the vapor and, in turn, the glass. The result is some of the purest glass imaginable.

Pure silica glass, either with or without intentionally small amounts of dopants, is also able to withstand vast temperature changes with virtually no expansion or contraction. That's an essential quality for glass products that, for example, must perform reliably in outer space.

The process is also highly scalable, meaning that Corning can ramp up production of products like specialty optical fiber and make sure every spool is of the highest quality.

And OVD allows for very tight control of dopants added to the silica, which can result in the desired specific optical attributes in the glass – a precise refractive index for light going through fiber, for example. That superior process control capability, says Michelle, "allows us to achieve a comprehensive  product portfolio."

How it's evolved

Legendary Corning inventor Dr. Frank Hyde began the work in the 1930s that would eventually develop into vapor deposition. Corning revolutionized the process in the 1970s in creating the world's first low-loss optical fiber.

Continuous improvements over the years – most of a highly proprietary nature -- have enabled Corning to make the process increasingly efficient. That's one reason Corning is the leader in optical fiber manufacturing.

Why we excel at it

Although fiber makers can purchase manufacturing equipment on the open market, Corning designs and builds its own.

And the equipment's top-notch quality stems directly from Corning's fundamental understanding of the materials and the science – chemistry and physics – that combine to make the process.

Product demands, particularly in optical fiber, have challenged Corning to continue its investments in improving vapor deposition.

"We've had to grow our understanding -- and in turn, our capability for both our process control and our machine design – in order to meet market demands," said Gausman.

"Because of our legacy and decades of fundamentally understanding the work, we've been able to evolve the product portfolio. And that's what we'll continue to do."