Grantee Research Project Results
Final Report: Corrosion and Wear Resistant Coatings From Recycled Industry Waste
EPA Contract Number: EPD04034Title: Corrosion and Wear Resistant Coatings From Recycled Industry Waste
Investigators: Henry, Jack
Small Business: Environmental Abrasives LLC
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2004 through August 31, 2004
Project Amount: $69,940
RFA: Small Business Innovation Research (SBIR) - Phase I (2004) RFA Text | Recipients Lists
Research Category: SBIR - Waste , Hazardous Waste/Remediation , Small Business Innovation Research (SBIR)
Description:
Environmental Abrasives, LLC (EA), a Boise, ID-based company, was founded in the year 2000. EA is a spin-off of a 45 year-old, heavy highway construction firm, Nelson Construction Company, also of Boise, ID. Originally, the concept for EA evolved from the development of its patented process of comminuting (crushing) high-grade engineered fused aluminum oxide ceramic (alumina) scrap from CoorsTek, Inc., to produce a spectrum of alumina grains and powders as illustrated in Figure 1. Its core objectives subsequently evolved into a concept of helping to improve the environment by locating, collecting, and reprocessing manufactured waste ceramics and in turn using these resulting recycled products in useful industrial applications. Founding tenets for EA became the identification and development of new construction materials and practices that contribute to an improved environment. Currently, EA recycles from three main manufacturing companies to create alumina ceramic abrasive grains, alumina ceramic technical powders, and pure polycrystalline silicon (polysilicon) technical powders.
Figure 1. Environmental Abrasives, LLC’s patented process of comminuting high-grade engineered fused aluminum oxide ceramic scrap to produce a spectrum of alumina grains and powders.
The goal of this research project was to explore, characterize, and test EA’s comminuted alumina grains and powders as cost-effective, environmentally friendly, and corrosion- and wear-resistant coatings for ferrous and aluminum-based materials. EA accepts only high-grade engineered alumina scrap from CoorsTek, Inc. CoorsTek, Inc., has specially designed and tested their alumina material and produces products for a broad range of industries. EA’s recycling and comminution process retains the purity and chemistry of CoorsTek’s engineered alumina material.
This scrap material varies in alumina purity from 85 percent to 96 percent, with the remaining balance of mostly silicon dioxide and magnesium oxide. The size of the CoorsTek, Inc., scrap can be as small as 0.5 in3 to nearly 1 ft3. Once comminuted, the mixture is classified and purified to generate refined abrasive grains and sprayable alumina powders, referred to as EA Alumina Grains and EA Alumina Powders. To examine the value of recycled alumina scrap as useful alumina grains and powders, EA developed a Phase I proposal to investigate the performance of its alumina in coatings as fillers for ceramic-based adhesives and as plasma-sprayable powders.
The specific goals of this research project were to: (1) produce EA alumina grains and powders from recycled ceramic industrial scrap, (2) clean and surface profile iron and aluminum-based substrates for testing, (3) coat substrates using thermal spray and adhesive bond processes, and (4) test the samples and controls. The basic approach was to compare test results and production costs for EA alumina-coated substrates (samples) to substrates coated from comparable commercial (CC) alumina coatings (controls). Successful completion of these four major segments was to provide data to meet the overall goal of demonstrating that EA alumina plasma coatings and EA ceramic adhesive coatings cost less than, and have equivalent wear and corrosion protection performance compared to, CC alumina plasma coatings and CC ceramic adhesive coatings. An equally acceptable result was to prove that EA alumina plasma coatings and EA ceramic adhesive coatings had similar coating costs and better wear and corrosion protection performance than the controls.
Summary/Accomplishments (Outputs/Outcomes):
During Phase 1, EA concentrated on two dramatically different technologies with respect to industrial coatings (plasma spray and ceramic adhesive coatings) and successfully achieved most of the originally stated goals. EA initiated the research by identifying and establishing a process for transforming high-grade industrial alumina scrap into low-cost, high-performance commercial powders and grains. Targeting the specifications of CC products on the market that were 75 percent to nearly 1,400 percent more expensive than EA’s products, EA further refined an assortment of high-quality powders and grains to meet specific industry needs, which include: (1) coarse grains for cleaning and surface profiling metal surfaces; (2) fine, tightly controlled particle sizes for plasma spray coating applications; (3) and coarse, medium, and fine particle sizes for ceramic adhesive coating applications.
Through a series of tests, EA identified the coating characteristics of thermally sprayed EA alumina powders and compared them directly with the coating characteristics of industry standard CC powders. EA’s powders performed comparably to the CC powders for impact resistance, thermal tolerance, and tensile strength, and better than the CC powders in tests for abrasion and corrosion resistance. Although EA’s powders performed better and cost much less than CC powders, the commercial opportunities are still challenging. EA creates its alumina powders by recycling and comminuting CoorsTek’s waste stream of advanced engineered alumina ceramics, and EA’s average alumina compositions are approximately 89 percent. Commercialization research, however, revealed that higher alumina purity currently is required by most plasma spray applications. EA must make its opportunities in the plasma spray market through qualification tests in conjunction with end users.
Simultaneously to the plasma spray research, EA compared the performance and durability of EA alumina grains and CC alumina grains combined with a commercially available adhesive. These ceramic adhesives also were tested for impact resistance and both performed comparably. The comparative test evaluations of abrasion and erosion tolerance were, however, invalidated because of differing ceramic blends in the adhesive mix of the sample and control coatings. Lacking the time to create and test new samples, full characterization of EA ceramic adhesive coatings will be a followup activity to this research project.
Conclusions:
A prime objective, or project success criterion, was defined as equal wear and corrosion protection performance and less cost of EA samples versus industry controls. EA alumina plasma coatings performed better than the CC alumina plasma coatings in wear and corrosion protection, and the cost of the EA alumina plasma coatings was significantly less. Although the prime objective was met for the plasma coatings, full characterization was incomplete for the ceramic adhesive coatings. The cost of the EA ceramic adhesive coatings was less expensive than the industry controls. Nevertheless, followup testing will be required to assess the performance potential of the EA ceramic adhesive coatings versus industry controls. In industry, however, two companies currently use EA grains for ceramic adhesive coatings in industrial applications. Both companies recently replaced their comparable industrial grains with EA’s less costly alumina materials.
Industries, such as the semiconductor and aerospace industries, use thinner, lighter duty alumina plasma spray coatings and require product qualifications. Product qualifications can be time consuming and expensive, but are necessary for industry acceptance and continued marketing. The heavy construction and mining industries, however, use thicker, heavy-duty ceramic adhesive coatings and appear to be more concerned with coating performance and costs results. With successful testing of EA ceramic adhesives and EA’s connections to heavy industry, the commercialization opportunities for EA grains in ceramic adhesive coatings is significant in terms of potential high-volume usage and easier industry acceptance.
Supplemental Keywords:
alumina coatings, recycling, alumina scrap, comminuted alumina grains, alumina powder, silicon dioxide, magnesium oxide, plasma coatings, wear resistance, corrosion resistance, recycling industry, SBIR,, RFA, Scientific Discipline, TREATMENT/CONTROL, Waste, Sustainable Industry/Business, Sustainable Environment, Municipal, Environmental Chemistry, Technology, Technology for Sustainable Environment, New/Innovative technologies, Environmental Engineering, clean technologies, waste reduction, alumina powder, municipal waste, ceramic waste, recycling, coating formulations, ceramic industrial waste, pollution preventionThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.